Bump karma from 3.1.4 to 6.3.2 (#417)

Bumps [karma](https://github.com/karma-runner/karma) from 3.1.4 to 6.3.2.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v3.1.4...v6.3.2)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -23,7 +23,7 @@
     "grunt-jsdoc": "^2.1.0",
     "grunt-karma": "^4.0.0",
     "grunt-mocha-test": "^0.13.3",
-    "karma": "^3.1.4",
+    "karma": "^6.3.2",
     "karma-chai": "^0.1.0",
     "chai": "*",
     "karma-firefox-launcher": "^1.0.0",