Bump VERSION to 1.14.3

• Diff: https://gitlab.com/gitlab-org/gitlab-triage/-/compare/v1.14.2...v1.14.3

• Release notes:

### Other changes (tooling, technical debt)

- !185 Modify query for fetching issue/merge request thread count

• Checklist before merging:

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

• Checklist after merging:

  • Update the release notes for the newly created tag.