chore(deps): update dependency chai to v4.4.0

package.json

@@ -55,7 +55,7 @@
     "babel-plugin-istanbul": "5.0.1",
     "babel-plugin-transform-async-to-generator": "6.24.1",
     "babel-preset-es2015": "6.24.1",
-    "chai": "4.1.2",
+    "chai": "4.4.0",
     "chai-as-promised": "7.1.1",
     "child-process-promise": "2.2.1",
     "codecov": "3.6.5",