Bump VERSION to 6.10.0

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/v6.9.0...67320134

• Release notes:

### New scenarios and scenario updates

- !568 Show which jobs are quarantined in test session.

### Fixes

- !570 Remove docker container if exists before run.
- !575 Auto-paginate issue discussions to allow to match existing errors.

### Other changes (CI, backstage)

- !576 Update the dependency on the `gitlab` gem to `~> 4.16.1`.
- !577 Stop logging when a note doesn't contain an error trace.
- !579 Tweak the log output when the testcase issue is not updated

• Checklist before merging:

  • Diff link is up-to-date.
  • Based on the diff, lib/gitlab/qa/version.rb is updated, according to SemVer.
  • Release notes are accurate.

• Checklist after merging:

  • Create a tag for the new release version.