diff --git a/package.json b/package.json
index 19d488e..ecb3019 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "vue-template-compiler": "2.6.10",
     "webpack": "4.32.0",
     "webpack-cli": "3.3.2",
-    "webpack-dev-server": "3.4.1",
+    "webpack-dev-server": "3.9.0",
     "webpack-merge": "4.2.1"
   },
   "dependencies": {
diff --git a/yarn.lock b/yarn.lock
index fcd5ff1..89fbe4f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1008,10 +1008,17 @@ async-each@^1.0.1:
   resolved "https://registry.yarnpkg.com/async-each/-/async-each-1.0.3.tgz#b727dbf87d7651602f06f4d4ac387f47d91b0cbf"
   integrity sha512-z/WhQ5FPySLdvREByI2vZiTWwCnF0moMJ1hK9YQwDTHKh6I7/uSckMetoRGb5UBZPC1z0jlw+n/XCgjeH7y1AQ==
 
-async@^1.5.2:
-  version "1.5.2"
-  resolved "https://registry.yarnpkg.com/async/-/async-1.5.2.tgz#ec6a61ae56480c0c3cb241c95618e20892f9672a"
-  integrity sha1-7GphrlZIDAw8skHJVhjiCJL5Zyo=
+async-limiter@~1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.1.tgz#dd379e94f0db8310b08291f9d64c3209766617fd"
+  integrity sha512-csOlWGAcRFJaI6m+F2WKdnMKr4HhdhFVBk0H/QbJFMCr+uO2kwohwXQPxw/9OCxp05r5ghVBFSyioixx3gfkNQ==
+
+async@^2.6.2:
+  version "2.6.3"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.3.tgz#d72625e2344a3656e3a3ad4fa749fa83299d82ff"
+  integrity sha512-zflvls11DCy+dQWzTW2dzuilv8Z5X/pjfmZOWba6TNIVDm+2UDaJmXSOXlasHKfNBs8oo3M0aT50fDEWfKZjXg==
+  dependencies:
+    lodash "^4.17.14"
 
 atob@^2.1.1:
   version "2.1.2"
@@ -1335,10 +1342,10 @@ chokidar@^2.0.2:
   optionalDependencies:
     fsevents "^1.2.7"
 
-chokidar@^2.1.6:
-  version "2.1.6"
-  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-2.1.6.tgz#b6cad653a929e244ce8a834244164d241fa954c5"
-  integrity sha512-V2jUo67OKkc6ySiRpJrjlpJKl9kDuG+Xb8VgsGzb+aEouhgS1D0weyPU4lEzdAcsCAvrih2J2BqyXqHWvVLw5g==
+chokidar@^2.1.8:
+  version "2.1.8"
+  resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-2.1.8.tgz#804b3a7b6a99358c3c5c61e71d8728f041cff917"
+  integrity sha512-ZmZUazfOzf0Nve7duiCKD23PFSCs4JPoYyccjUFF3aQkQadqBhfzhjkwBH2mNOG9cTBwhamM37EIsIkZw3nRgg==
   dependencies:
     anymatch "^2.0.0"
     async-each "^1.0.1"
@@ -1718,7 +1725,7 @@ debug@2.6.9, debug@^2.2.0, debug@^2.3.3, debug@^2.6.8, debug@^2.6.9:
   dependencies:
     ms "2.0.0"
 
-debug@^3.2.5, debug@^3.2.6:
+debug@^3.1.1, debug@^3.2.5, debug@^3.2.6:
   version "3.2.6"
   resolved "https://registry.yarnpkg.com/debug/-/debug-3.2.6.tgz#e83d17de16d8a7efb7717edbe5fb10135eee629b"
   integrity sha512-mel+jf7nrtEl5Pn1Qx46zARXKDpBbvzezse7p7LqINmdoIk8PYP5SySaxEmYv6TZ0JyEKA1hsCId6DIhgITtWQ==
@@ -2253,10 +2260,10 @@ expand-tilde@^2.0.0, expand-tilde@^2.0.2:
   dependencies:
     homedir-polyfill "^1.0.1"
 
-express@^4.17.0:
-  version "4.17.0"
-  resolved "https://registry.yarnpkg.com/express/-/express-4.17.0.tgz#288af62228a73f4c8ea2990ba3b791bb87cd4438"
-  integrity sha512-1Z7/t3Z5ZnBG252gKUPyItc4xdeaA0X934ca2ewckAsVsw9EG71i++ZHZPYnus8g/s5Bty8IMpSVEuRkmwwPRQ==
+express@^4.17.1:
+  version "4.17.1"
+  resolved "https://registry.yarnpkg.com/express/-/express-4.17.1.tgz#4491fc38605cf51f8629d39c2b5d026f98a4c134"
+  integrity sha512-mHJ9O79RqluphRrcw2X/GTh3k9tVv8YcoyY4Kkh4WDMUYKRZUq0h1o0w2rrrxBqM7VoeUVqgb27xlEMXTnYt4g==
   dependencies:
     accepts "~1.3.7"
     array-flatten "1.1.1"
@@ -2802,7 +2809,7 @@ http-parser-js@>=0.4.0:
   resolved "https://registry.yarnpkg.com/http-parser-js/-/http-parser-js-0.5.0.tgz#d65edbede84349d0dc30320815a15d39cc3cbbd8"
   integrity sha512-cZdEF7r4gfRIq7ezX9J0T+kQmJNOub71dWbgAXVHDct80TKP4MCETtZQ31xyv38UwgzkWPYF/Xc0ge55dW9Z9w==
 
-http-proxy-middleware@^0.19.1:
+http-proxy-middleware@0.19.1:
   version "0.19.1"
   resolved "https://registry.yarnpkg.com/http-proxy-middleware/-/http-proxy-middleware-0.19.1.tgz#183c7dc4aa1479150306498c210cdaf96080a43a"
   integrity sha512-yHYTgWMQO8VvwNS22eLLloAkvungsKdKTLO8AJlftYIKNfJr3GK3zK0ZCfzDDGUBttdGc8xFy1mCitvNKQtC3Q==
@@ -2985,6 +2992,11 @@ ipaddr.js@1.9.0, ipaddr.js@^1.9.0:
   resolved "https://registry.yarnpkg.com/ipaddr.js/-/ipaddr.js-1.9.0.tgz#37df74e430a0e47550fe54a2defe30d8acd95f65"
   integrity sha512-M4Sjn6N/+O6/IXSJseKqHoFc+5FdGJ22sXqnjTpdZweHK64MzEPAyQZyEU3R/KRv2GLoa7nNtg/C2Ev6m7z+eA==
 
+is-absolute-url@^3.0.3:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/is-absolute-url/-/is-absolute-url-3.0.3.tgz#96c6a22b6a23929b11ea0afb1836c36ad4a5d698"
+  integrity sha512-opmNIX7uFnS96NtPmhWQgQx6/NYFgsUXYMllcfzwWKUMwfo8kku1TvE6hkNcH+Q1ts5cMVrsY7j0bxXQDciu9Q==
+
 is-accessor-descriptor@^0.1.6:
   version "0.1.6"
   resolved "https://registry.yarnpkg.com/is-accessor-descriptor/-/is-accessor-descriptor-0.1.6.tgz#a9e12cb3ae8d876727eeef3843f8a0897b5c98d6"
@@ -3349,10 +3361,15 @@ lodash@^4.17.11, lodash@^4.17.5:
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
   integrity sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==
 
-loglevel@^1.6.1:
-  version "1.6.1"
-  resolved "https://registry.yarnpkg.com/loglevel/-/loglevel-1.6.1.tgz#e0fc95133b6ef276cdc8887cdaf24aa6f156f8fa"
-  integrity sha1-4PyVEztu8nbNyIh82vJKpvFW+Po=
+lodash@^4.17.14:
+  version "4.17.15"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
+  integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
+
+loglevel@^1.6.4:
+  version "1.6.6"
+  resolved "https://registry.yarnpkg.com/loglevel/-/loglevel-1.6.6.tgz#0ee6300cc058db6b3551fa1c4bf73b83bb771312"
+  integrity sha512-Sgr5lbboAUBo3eXCSPL4/KoVz3ROKquOjcctxmHIt+vol2DrqTQe3SwkKKuYhEiWB5kYa13YyopJ69deJ1irzQ==
 
 loose-envify@^1.0.0:
   version "1.4.0"
@@ -3500,10 +3517,10 @@ mime@1.6.0:
   resolved "https://registry.yarnpkg.com/mime/-/mime-1.6.0.tgz#32cd9e5c64553bd58d19a568af452acff04981b1"
   integrity sha512-x0Vn8spI+wuJ1O6S7gnbaQg8Pxh4NNHb7KSINmEWKiPE4RKOplvijn+NkmYmmRgP68mc70j2EbeTFRsrswaQeg==
 
-mime@^2.4.2:
-  version "2.4.3"
-  resolved "https://registry.yarnpkg.com/mime/-/mime-2.4.3.tgz#229687331e86f68924e6cb59e1cdd937f18275fe"
-  integrity sha512-QgrPRJfE+riq5TPZMcHZOtm8c6K/yYrMbKIoRfapfiGLxS8OTeIfRhUGW5LU7MlRa52KOAGCfUNruqLrIBvWZw==
+mime@^2.4.4:
+  version "2.4.4"
+  resolved "https://registry.yarnpkg.com/mime/-/mime-2.4.4.tgz#bd7b91135fc6b01cde3e9bae33d659b63d8857e5"
+  integrity sha512-LRxmNwziLPT828z+4YkNzloCFC2YM4wrB99k+AV5ZbEyfGNWfG8SO1FUXLmLDBSo89NrJZ4DIWeLjy1CHGhMGA==
 
 mimic-fn@^1.0.0:
   version "1.2.0"
@@ -3581,7 +3598,7 @@ mixin-deep@^1.2.0:
     for-in "^1.0.2"
     is-extendable "^1.0.1"
 
-mkdirp@0.5.1, mkdirp@0.5.x, mkdirp@^0.5.0, mkdirp@^0.5.1, mkdirp@~0.5.0:
+mkdirp@0.5.1, mkdirp@^0.5.0, mkdirp@^0.5.1, mkdirp@~0.5.0:
   version "0.5.1"
   resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.1.tgz#30057438eac6cf7f8c4767f38648d6697d75c903"
   integrity sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=
@@ -3679,10 +3696,10 @@ nice-try@^1.0.4:
   resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
   integrity sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==
 
-node-forge@0.7.5:
-  version "0.7.5"
-  resolved "https://registry.yarnpkg.com/node-forge/-/node-forge-0.7.5.tgz#6c152c345ce11c52f465c2abd957e8639cd674df"
-  integrity sha512-MmbQJ2MTESTjt3Gi/3yG1wGpIMhUfcIypUCGtTizFR9IiccFwxSpfp0vtIZlkFclEqERemxfnSdZEMR9VqqEFQ==
+node-forge@0.9.0:
+  version "0.9.0"
+  resolved "https://registry.yarnpkg.com/node-forge/-/node-forge-0.9.0.tgz#d624050edbb44874adca12bb9a52ec63cb782579"
+  integrity sha512-7ASaDa3pD+lJ3WvXFsxekJQelBKRpne+GOVbLbtHYdd7pFspyeuJHnWfLplGf3SwKGbfs/aYl5V/JCIaHVUKKQ==
 
 node-libs-browser@^2.0.0:
   version "2.2.0"
@@ -3996,6 +4013,13 @@ p-map@^2.0.0:
   resolved "https://registry.yarnpkg.com/p-map/-/p-map-2.1.0.tgz#310928feef9c9ecc65b68b17693018a665cea175"
   integrity sha512-y3b8Kpd8OAN444hxfBbFfj1FY/RjtTd8tzYwhUqNYXx0fXx2iX4maP4Qr6qhIKbQXI02wTLAda4fYUbDagTUFw==
 
+p-retry@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/p-retry/-/p-retry-3.0.1.tgz#316b4c8893e2c8dc1cfa891f406c4b422bebf328"
+  integrity sha512-XE6G4+YTTkT2a0UWb2kjZe8xNwf8bIbnqpc/IS/idOBVhyves0mK5OJgeocjx7q5pvX/6m23xuzVPYT1uGM73w==
+  dependencies:
+    retry "^0.12.0"
+
 p-try@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/p-try/-/p-try-1.0.0.tgz#cbc79cdbaf8fd4228e13f621f2b1a237c1b207b3"
@@ -4181,14 +4205,14 @@ pkg-dir@^3.0.0:
   dependencies:
     find-up "^3.0.0"
 
-portfinder@^1.0.20:
-  version "1.0.20"
-  resolved "https://registry.yarnpkg.com/portfinder/-/portfinder-1.0.20.tgz#bea68632e54b2e13ab7b0c4775e9b41bf270e44a"
-  integrity sha512-Yxe4mTyDzTd59PZJY4ojZR8F+E5e97iq2ZOHPz3HDgSvYC5siNad2tLooQ5y5QHyQhc3xVqvyk/eNA3wuoa7Sw==
+portfinder@^1.0.25:
+  version "1.0.25"
+  resolved "https://registry.yarnpkg.com/portfinder/-/portfinder-1.0.25.tgz#254fd337ffba869f4b9d37edc298059cb4d35eca"
+  integrity sha512-6ElJnHBbxVA1XSLgBp7G1FiCkQdlqGzuF7DswL5tcea+E8UpuvPU7beVAjjRwCioTS9ZluNbu+ZyRvgTsmqEBg==
   dependencies:
-    async "^1.5.2"
-    debug "^2.2.0"
-    mkdirp "0.5.x"
+    async "^2.6.2"
+    debug "^3.1.1"
+    mkdirp "^0.5.1"
 
 posix-character-classes@^0.1.0:
   version "0.1.1"
@@ -4620,6 +4644,11 @@ ret@~0.1.10:
   resolved "https://registry.yarnpkg.com/ret/-/ret-0.1.15.tgz#b8a4825d5bdb1fc3f6f53c2bc33f81388681c7bc"
   integrity sha512-TTlYpa+OL+vMMNG24xSlQGEJ3B/RzEfUlLct7b5G/ytav+wPrplCpVMFuwzXbkecJrb6IYo1iFb0S9v37754mg==
 
+retry@^0.12.0:
+  version "0.12.0"
+  resolved "https://registry.yarnpkg.com/retry/-/retry-0.12.0.tgz#1b42a6266a21f07421d1b0b54b7dc167b01c013b"
+  integrity sha1-G0KmJmoh8HQh0bC1S33BZ7AcATs=
+
 rimraf@2.6.3, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.6.2, rimraf@^2.6.3:
   version "2.6.3"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.3.tgz#b2d104fe0d8fb27cf9e0a1cda8262dd3833c6cab"
@@ -4692,12 +4721,12 @@ select-hose@^2.0.0:
   resolved "https://registry.yarnpkg.com/select-hose/-/select-hose-2.0.0.tgz#625d8658f865af43ec962bfc376a37359a4994ca"
   integrity sha1-Yl2GWPhlr0Psliv8N2o3NZpJlMo=
 
-selfsigned@^1.10.4:
-  version "1.10.4"
-  resolved "https://registry.yarnpkg.com/selfsigned/-/selfsigned-1.10.4.tgz#cdd7eccfca4ed7635d47a08bf2d5d3074092e2cd"
-  integrity sha512-9AukTiDmHXGXWtWjembZ5NDmVvP2695EtpgbCsxCa68w3c88B+alqbmZ4O3hZ4VWGXeGWzEVdvqgAJD8DQPCDw==
+selfsigned@^1.10.7:
+  version "1.10.7"
+  resolved "https://registry.yarnpkg.com/selfsigned/-/selfsigned-1.10.7.tgz#da5819fd049d5574f28e88a9bcc6dbc6e6f3906b"
+  integrity sha512-8M3wBCzeWIJnQfl43IKwOmC4H/RAp50S8DF60znzjW5GVqTcSe2vWclt7hmYVPkKPlHWOu5EaWOMZ2Y6W8ZXTA==
   dependencies:
-    node-forge "0.7.5"
+    node-forge "0.9.0"
 
 "semver@2 || 3 || 4 || 5", semver@^5.3.0, semver@^5.4.1, semver@^5.5.0, semver@^5.5.1, semver@^5.6.0:
   version "5.7.0"
@@ -4709,6 +4738,11 @@ semver@^6.0.0:
   resolved "https://registry.yarnpkg.com/semver/-/semver-6.0.0.tgz#05e359ee571e5ad7ed641a6eec1e547ba52dea65"
   integrity sha512-0UewU+9rFapKFnlbirLi3byoOuhrSsli/z/ihNnvM24vgF+8sNBiI1LZPBSH9wJKUwaUbw+s3hToDLCXkrghrQ==
 
+semver@^6.3.0:
+  version "6.3.0"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-6.3.0.tgz#ee0a64c8af5e8ceea67687b133761e1becbd1d3d"
+  integrity sha512-b39TBaTSfV6yBrapU89p5fKekE2m/NwnDocOVruQFS1/veMgdzuPcnOM34M6CwxW8jH/lxEa5rBoDeUwu5HHTw==
+
 send@0.17.1:
   version "0.17.1"
   resolved "https://registry.yarnpkg.com/send/-/send-0.17.1.tgz#c1d8b059f7900f7466dd4938bdc44e11ddb376c8"
@@ -4865,10 +4899,10 @@ snapdragon@^0.8.1:
     source-map-resolve "^0.5.0"
     use "^3.1.0"
 
-sockjs-client@1.3.0:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/sockjs-client/-/sockjs-client-1.3.0.tgz#12fc9d6cb663da5739d3dc5fb6e8687da95cb177"
-  integrity sha512-R9jxEzhnnrdxLCNln0xg5uGHqMnkhPSTzUZH2eXcR03S/On9Yvoq2wyUZILRUhZCNVu2PmwWVoyuiPz8th8zbg==
+sockjs-client@1.4.0:
+  version "1.4.0"
+  resolved "https://registry.yarnpkg.com/sockjs-client/-/sockjs-client-1.4.0.tgz#c9f2568e19c8fd8173b4997ea3420e0bb306c7d5"
+  integrity sha512-5zaLyO8/nri5cua0VtOrFXBPK1jbL4+1cebT/mmKA1E1ZXOvJrII75bPu0l0k843G/+iAbhEqzyKr0w/eCCj7g==
   dependencies:
     debug "^3.2.5"
     eventsource "^1.0.7"
@@ -4962,10 +4996,10 @@ spdy-transport@^3.0.0:
     readable-stream "^3.0.6"
     wbuf "^1.7.3"
 
-spdy@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/spdy/-/spdy-4.0.0.tgz#81f222b5a743a329aa12cea6a390e60e9b613c52"
-  integrity sha512-ot0oEGT/PGUpzf/6uk4AWLqkq+irlqHXkrdbk51oWONh3bxQmBuljxPNl66zlRRcIJStWq0QkLUCPOPjgjvU0Q==
+spdy@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/spdy/-/spdy-4.0.1.tgz#6f12ed1c5db7ea4f24ebb8b89ba58c87c08257f2"
+  integrity sha512-HeZS3PBdMA+sZSu0qwpCxl3DeALD5ASx8pAX0jZdKXSpPWbQ6SYGnlg3BBmYLx5LtiZrmkAZfErCm2oECBcioA==
   dependencies:
     debug "^4.1.0"
     handle-thing "^2.0.0"
@@ -5534,50 +5568,54 @@ webpack-cli@3.3.2:
     v8-compile-cache "^2.0.2"
     yargs "^12.0.5"
 
-webpack-dev-middleware@^3.7.0:
-  version "3.7.0"
-  resolved "https://registry.yarnpkg.com/webpack-dev-middleware/-/webpack-dev-middleware-3.7.0.tgz#ef751d25f4e9a5c8a35da600c5fda3582b5c6cff"
-  integrity sha512-qvDesR1QZRIAZHOE3iQ4CXLZZSQ1lAUsSpnQmlB1PBfoN/xdRjmge3Dok0W4IdaVLJOGJy3sGI4sZHwjRU0PCA==
+webpack-dev-middleware@^3.7.2:
+  version "3.7.2"
+  resolved "https://registry.yarnpkg.com/webpack-dev-middleware/-/webpack-dev-middleware-3.7.2.tgz#0019c3db716e3fa5cecbf64f2ab88a74bab331f3"
+  integrity sha512-1xC42LxbYoqLNAhV6YzTYacicgMZQTqRd27Sim9wn5hJrX3I5nxYy1SxSd4+gjUFsz1dQFj+yEe6zEVmSkeJjw==
   dependencies:
     memory-fs "^0.4.1"
-    mime "^2.4.2"
+    mime "^2.4.4"
+    mkdirp "^0.5.1"
     range-parser "^1.2.1"
     webpack-log "^2.0.0"
 
-webpack-dev-server@3.4.1:
-  version "3.4.1"
-  resolved "https://registry.yarnpkg.com/webpack-dev-server/-/webpack-dev-server-3.4.1.tgz#a5fd8dec95dec410098e7d9a037ff9405395d51a"
-  integrity sha512-CRqZQX2ryMtrg0r3TXQPpNh76eM1HD3Wmu6zDBxIKi/d2y+4aa28Ia8weNT0bfgWpY6Vs3Oq/K8+DjfbR+tWYw==
+webpack-dev-server@3.9.0:
+  version "3.9.0"
+  resolved "https://registry.yarnpkg.com/webpack-dev-server/-/webpack-dev-server-3.9.0.tgz#27c3b5d0f6b6677c4304465ac817623c8b27b89c"
+  integrity sha512-E6uQ4kRrTX9URN9s/lIbqTAztwEPdvzVrcmHE8EQ9YnuT9J8Es5Wrd8n9BKg1a0oZ5EgEke/EQFgUsp18dSTBw==
   dependencies:
     ansi-html "0.0.7"
     bonjour "^3.5.0"
-    chokidar "^2.1.6"
+    chokidar "^2.1.8"
     compression "^1.7.4"
     connect-history-api-fallback "^1.6.0"
     debug "^4.1.1"
     del "^4.1.1"
-    express "^4.17.0"
+    express "^4.17.1"
     html-entities "^1.2.1"
-    http-proxy-middleware "^0.19.1"
+    http-proxy-middleware "0.19.1"
     import-local "^2.0.0"
     internal-ip "^4.3.0"
     ip "^1.1.5"
+    is-absolute-url "^3.0.3"
     killable "^1.0.1"
-    loglevel "^1.6.1"
+    loglevel "^1.6.4"
     opn "^5.5.0"
-    portfinder "^1.0.20"
+    p-retry "^3.0.1"
+    portfinder "^1.0.25"
     schema-utils "^1.0.0"
-    selfsigned "^1.10.4"
-    semver "^6.0.0"
+    selfsigned "^1.10.7"
+    semver "^6.3.0"
     serve-index "^1.9.1"
     sockjs "0.3.19"
-    sockjs-client "1.3.0"
-    spdy "^4.0.0"
+    sockjs-client "1.4.0"
+    spdy "^4.0.1"
     strip-ansi "^3.0.1"
     supports-color "^6.1.0"
     url "^0.11.0"
-    webpack-dev-middleware "^3.7.0"
+    webpack-dev-middleware "^3.7.2"
     webpack-log "^2.0.0"
+    ws "^6.2.1"
     yargs "12.0.5"
 
 webpack-log@^2.0.0:
@@ -5697,6 +5735,13 @@ write@1.0.3:
   dependencies:
     mkdirp "^0.5.1"
 
+ws@^6.2.1:
+  version "6.2.1"
+  resolved "https://registry.yarnpkg.com/ws/-/ws-6.2.1.tgz#442fdf0a47ed64f59b6a5d8ff130f4748ed524fb"
+  integrity sha512-GIyAXC2cB7LjvpgMt9EKS2ldqr0MTrORaleiOno6TweZ6r3TKtoFQWay/2PceJ3RuBasOHzXNn5Lrw1X0bEjqA==
+  dependencies:
+    async-limiter "~1.0.0"
+
 xtend@^4.0.0, xtend@~4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"