CI: Remove Node.js 7 and add 8 and 10. (#1071)

Also remove the obsolete `sudo: false` from Travis.

.travis.yml

@@ -1,9 +1,9 @@
-sudo: false
 language: node_js
 cache: npm
 node_js:
   - 4
   - 6
-  - 7
+  - 8
+  - 10
 matrix:
   fast_finish: true

appveyor.yml

@@ -1,4 +1,4 @@
-# http://www.appveyor.com/docs/appveyor-yml
+# https://www.appveyor.com/docs/appveyor-yml/
 
 version: "{build}"
 
@@ -11,7 +11,8 @@ environment:
   matrix:
     - nodejs_version: 4
     - nodejs_version: 6
-    - nodejs_version: 7
+    - nodejs_version: 8
+    - nodejs_version: 10
 
 install:
   - ps: Install-Product node $env:nodejs_version
@@ -20,11 +21,12 @@ install:
 build: off
 
 test_script:
-  - node --version && npm --version
+  - node --version
+  - npm --version
   - npm test
 
 matrix:
   fast_finish: true
 
 cache:
-  - node_modules -> package.json    # local npm modules
+  - 'node_modules -> package.json' # local npm modules