chore(package): update mocha to version 3.4.2

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -41,7 +41,7 @@
     "coveralls": "^2.11.9",
     "eslint": "^2.12.0",
     "istanbul": "^0.4.3",
-    "mocha": "^2.5.3",
+    "mocha": "^3.4.2",
     "pre-commit": "^1.1.3",
     "supertest": "^1.2.0"
   }