Merge pull request #34 from mrsteele/greenkeeper/chai-4.0.2

Update chai to the latest version 🚀

Author: mrsteele

package.json

@@ -44,7 +44,7 @@
     "babel-eslint": "^7.2.3",
     "babel-preset-es2015": "^6.9.0",
     "babel-register": "^6.9.0",
-    "chai": "^3.5.0",
+    "chai": "^4.0.2",
     "commitizen": "^2.8.2",
     "cz-conventional-changelog": "^2.0.0",
     "mocha": "^3.4.1",