Upgrade karma to 3.0

Author: Steven Musumeche

package.json

@@ -92,7 +92,7 @@
     "isparta-loader": "^2.0.0",
     "jsdom": "^12.0.0",
     "jsdom-global": "^3.0.2",
-    "karma": "^2.0.0",
+    "karma": "^3.0.0",
     "karma-babel-preprocessor": "^6.0.1",
     "karma-chrome-launcher": "^2.2.0",
     "karma-coverage": "^1.1.1",