chore(package): update mocha to version 6.1.3

Closes #13

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "gulp-mocha": "^3.0.1",
     "gulp-util": "^3.0.7",
     "gulp-watch": "^4.3.5",
-    "mocha": "^3.1.2",
+    "mocha": "^6.1.3",
     "redux": "^3.0.4",
     "require-dir": "^0.3.0",
     "sinon": "^1.17.2"