Bump version to 6.1.3

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/v6.1.2...a4919dd9b2d7253e60bcea83476d109e1f92eb9c

• Release notes:

### Fixes

- !527 Retry reporting on more errors
- !518 Make the RSpec JSON formatter more like the JUnit formatter

### Other changes (CI, backstage)

- !524 Allow failure on kubernetes job while qa tunnel discussion
- !523 Enable reporting pipelines triggered from ops

• 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.