chore(package): update mocha to version 4.1.0

Closes #22

Author: greenkeeper[bot]

package.json

@@ -16,7 +16,7 @@
     "amqplib": "^0.5.1",
     "chai": "~4.0.0",
     "coffee-script": "^1.8.0",
-    "mocha": "~3.4.2",
+    "mocha": "~4.1.0",
     "msgflo": "^0.10.0",
     "mqtt": "~2.8.0"
   },