Bump karma from 6.3.20 to 6.4.0 (#986)
Bump karma from 6.3.20 to 6.4.0 (#986)

Bumps [karma](https://github.com/karma-runner/karma) from 6.3.20 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](https://github.com/karma-runner/karma/compare/v6.3.20...v6.4.0)

---
updated-dependencies:
- dependency-name: karma
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
publiclab/Leaflet.DistortableImage,publiclab/Leaflet.DistortableImage