chore(package): update mocha to version 4.1.0

Closes #9

Author: greenkeeper[bot]

package.json

@@ -13,7 +13,7 @@
   "description": "",
   "devDependencies": {
     "chai": "^4.0.1",
-    "mocha": "^3.3.0",
+    "mocha": "^4.1.0",
     "source-map-support": "^0.4.0",
     "typescript": "^2.3.2",
     "typings": "^2.1.1"