build(deps-dev): bump karma from 5.0.2 to 6.4.0

Bumps [karma](https://github.com/karma-runner/karma) from 5.0.2 to 6.4.0.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v5.0.2...v6.4.0)

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

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

Author: dependabot[bot]