chore(package): update mocha to version 6.1.4

Closes #13

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "eslint-plugin-prettier": "^2.6.2",
     "greenkeeper-lockfile": "^1.15.1",
     "husky": "^1.0.0-rc.13",
-    "mocha": "^5.2.0",
+    "mocha": "^6.1.4",
     "nyc": "^12.0.2",
     "prettier": "^1.13.7",
     "script-loader": "^0.7.2",