Update dependency karma to v6 [SECURITY]

Author: renovate[bot]

package.json

@@ -66,7 +66,7 @@
     "jsdoc": "^3.4.3",
     "jsdom": "~13.2.0",
     "json-loader": "^0.5.4",
-    "karma": "1.3.0",
+    "karma": "6.3.16",
     "karma-coverage": "^1.1.1",
     "karma-jasmine": "1.0.2",
     "karma-jsdom-launcher": "~7.0.0",