Merge pull request #3 from Leelow/greenkeeper/mocha-4.0.0

Update mocha to the latest version 🚀

Author: Leelow

package.json

@@ -16,7 +16,7 @@
   },
   "devDependencies": {
     "istanbul": "^0.4.5",
-    "mocha": "^3.2.0",
+    "mocha": "^4.0.0",
     "standard": "^10.0.0",
     "codacy-coverage": "^2.0.1"
   },