Update dependency karma to v6 [SECURITY]

Author: renovate[bot]

package.json

@@ -83,7 +83,7 @@
     "sinon": "^1.16.1",
     "chai-as-promised": "^5.1.0",
     "chai-things": "^0.2.0",
-    "karma": "~0.13.3",
+    "karma": "~6.3.16",
     "karma-firefox-launcher": "~0.1.6",
     "karma-script-launcher": "~0.2.0",
     "karma-chrome-launcher": "~0.2.0",