Bump karma from 1.6.0 to 6.3.16

Bumps [karma](https://github.com/karma-runner/karma) from 1.6.0 to 6.3.16.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v1.6.0...v6.3.16)

---
updated-dependencies:
- dependency-name: karma
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -93,7 +93,7 @@
     "istanbul": "^1.1.0-alpha.1",
     "jsdom": "^9.12.0",
     "json-loader": "^0.5.4",
-    "karma": "^1.6.0",
+    "karma": "^6.3.16",
     "karma-mocha": "^1.3.0",
     "karma-mocha-reporter": "^2.2.3",
     "karma-phantomjs-launcher": "^1.0.4",