chore(package): update mocha to version 7.1.1

Closes #45

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "jsdom": "^13.0.0",
     "jsdom-global": "^3.0.2",
     "load-grunt-tasks": "^4.0.0",
-    "mocha": "^6.0.0",
+    "mocha": "^7.1.1",
     "nyc": "^14.0.0",
     "unexpected": "^11.0.1"
   },