chore(package): update karma to version 4.2.0

Closes #144

Author: greenkeeper[bot]

package.json

@@ -40,7 +40,7 @@
     "codelyzer": "~4.1.0",
     "jasmine-core": "~2.8.0",
     "jasmine-spec-reporter": "~4.2.0",
-    "karma": "~2.0.0",
+    "karma": "~4.2.0",
     "karma-chrome-launcher": "~2.2.0",
     "karma-cli": "~1.0.1",
     "karma-coverage-istanbul-reporter": "^1.3.0",