chore(package): update karma-webpack to version 4.0.2

Closes #25

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
     "karma-firefox-launcher": "^1.0.0",
     "karma-jasmine": "^1.0.2",
     "karma-phantomjs-launcher": "^1.0.0",
-    "karma-webpack": "^2.0.0",
+    "karma-webpack": "^4.0.2",
     "ng-describe": "^1.8.0",
     "phantomjs-prebuilt": "^2.1.3",
     "semantic-release": "^8.0.0",