github-action: provenance

[v1v]

What does this pull request do?

Run the release steps partially for main - to validate things work smoothly before the release. It skips the below steps:

• rake release
• update branch
• slack notification

Enable provenance for the generated files in pkg/*.gem

Why is it important?

Secure

Checklist

• [ ] I have signed the Contributor License Agreement.
• [ ] My code follows the style guidelines of this project (See .rubocop.yml)
• [ ] I have rebased my changes on top of the latest main branch

• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes

• [ ] I have made corresponding changes to the documentation
• [ ] I have updated CHANGELOG.asciidoc
• [ ] I have updated supported-technologies.asciidoc
• [ ] Added an API method or config option? Document in which version this will be introduced

Related issues

Test

I created a test feature branch and triggered the release in dry-run mode:

• https://github.com/elastic/apm-agent-ruby/actions/runs/8819551134

See https://github.com/elastic/apm-agent-ruby/attestations