chore(package): update mocha to version 3.0.0 (#8)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -37,6 +37,6 @@
   "devDependencies": {
     "chai": "^3.5.0",
     "eslint": "~3.2.0",
-    "mocha": "^2.5.3"
+    "mocha": "^3.0.0"
   }
 }