chore: migrate Homebrew cask tap from openshift-pipelines to tektoncd

Context

The PAC Homebrew cask is currently published to openshift-pipelines/homebrew-pipelines-as-code via GoReleaser. This tap repo and the GoReleaser config need to be migrated to tektoncd.

Current config in .goreleaser.yml:79–106

homebrew_casks:
  - name: tektoncd-pac
    repository:
      owner: openshift-pipelines        # ← change to tektoncd
      name: homebrew-pipelines-as-code  # ← update to tektoncd tap repo name

Steps

1. Create or transfer openshift-pipelines/homebrew-pipelines-as-code → tektoncd/homebrew-pipelines-as-code (or equivalent tap name agreed on by the tektoncd community)
2. Update .goreleaser.yml repository.owner to tektoncd and repository.name to the new tap repo name
3. Ensure the GoReleaser bot token (stored in repo secrets) has write access to the new tap repo under tektoncd
4. Verify cask install works after next release:

   brew install tektoncd/pipelines-as-code/tektoncd-pac
   

Notes

• Users currently using brew install openshift-pipelines/pipelines-as-code/tektoncd-pac will need to update their tap.
• Consider adding a deprecation notice or redirect in the old tap if it remains accessible.

Start with .goreleaser.yml lines 79–106 and confirm the agreed tektoncd tap repository name. Check the release secret’s write access to that repository, then verify the documented brew install command after a release; done means the cask is published from the new tap and installs successfully.