chore(package): update mocha to version 4.0.1

Closes #75

Author: greenkeeper[bot]

package.json

@@ -54,7 +54,7 @@
     "core-js": "^2.4.1",
     "istanbul": "^0.4.3",
     "jsdoc": "^3.4.0",
-    "mocha": "^3.1.2",
+    "mocha": "^4.0.1",
     "mocha-lcov-reporter": "^1.2.0",
     "pug": "^2.0.0-alpha6",
     "supertest": "^3.0.0",