Update to version 5.1.0

• Diff: https://gitlab.com/gitlab-org/gitlab-styles/compare/v5.0.0...378a8e9a6b36787f04f244ad30dcb108e8ad1c08

• Release notes:

### New features and features updates

- !56 Upstream LineBreakAroundConditionalBlock Cop.

### Fixes

- !55 Fixes issue of looking at all empty rspec lines.

### Other changes (tooling, technical debt)

- !54 Bring auto-release to gitlab-styles.
- !57 Enable internal affairs cops

• Checklist before merging:

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

• Checklist after merging:

  • Update the release notes for the newly created tag.