chore(package): update mocha to version 4.1.0

Closes #12

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
     "chai": "^3.5.0",
     "coffee-script": "^1.12.5",
     "fbp": "^1.5.0",
-    "mocha": "^3.2.0",
+    "mocha": "^4.1.0",
     "microflo": "^0.3.47",
     "microflo-core": "^0.3.34"
   }