Merge pull request #720 from opensheetmusicdisplay/greenkeeper/karma-mocha-2.0.0

Update karma-mocha to the latest version 🚀

package.json

@@ -94,7 +94,7 @@
     "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^3.1.0",
     "karma-firefox-launcher": "^1.0.0",
-    "karma-mocha": "^1.1.1",
+    "karma-mocha": "^2.0.0",
     "karma-mocha-reporter": "^2.0.4",
     "karma-webpack": "^4.0.2",
     "karma-xml2js-preprocessor": "^0.0.3",