build: bump karma from 4.4.1 to 6.0.2

Bumps [karma](https://github.com/karma-runner/karma) from 4.4.1 to 6.0.2.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v4.4.1...v6.0.2)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -130,7 +130,7 @@
     "jasmine": "^3.5.0",
     "jasmine-core": "^3.5.0",
     "kagekiri": "^1.0.18",
-    "karma": "^4.4.1",
+    "karma": "^6.0.2",
     "karma-browserstack-launcher": "^1.6.0",
     "karma-chrome-launcher": "^3.1.0",
     "karma-firefox-launcher": "^2.0.0",