chore: update refs to v2.1.0-rc.1

[ramonpetgrave64]

#label:release v2.1.0-rc.1

Summary

Retrying the release, under a new tag, not rc.0.

The original release steps required doing a force push to update the tag in order to trigger workflow to produce the binaries as release artifacts. But now, repo settings make tags immutable, and I don't have permission to change the settings, so we'll try something different:

1. Use the changes in this PR's branch (not main) to cut a new pre-release under a new tag. This should produce the binaries and associate it with the release.
   • https://github.com/slsa-framework/slsa-github-generator/releases/tag/v2.1.0-rc.1
2. Merge this PR, after doing step 1.
3. The release and main should now be at the same commit sha

Testing Process

presubmits should pass

Checklist

• Review the contributing guidelines
• Add a reference to related issues in the PR description.
• Update documentation if applicable.
• Add unit tests if applicable.
• Add changes to the CHANGELOG if applicable.

[ramonpetgrave64]

The effect was not as expected. Main has a different commit hash

[ramonpetgrave64]

The only way may be to

1. create a new rc.2, merge it wihout the tests passing. Most tests should fail because the tag would not have existed yet.
2. create the new tag from main

[Hayden-IO]

I'm not following what is broken. Can we just tag a release from main and test against that?

[ramonpetgrave64]

I'm not following what is broken. Can we just tag a release from main and test against that?

We need a tagged release, where the released code's workflows also references workflows and actions at the same tag: the the code within v2.1.0-rc.1 must reference call v2.1.0-rc.1, not main. Under normal situations, you can't do this without overwriting a tag. But we don't have permissions to do that anymore.