Deprecate pushing a brew formula to stacklok/tap

[rdimitrov]

Summary

The following PR updates the release process so we no longer push a custom formula to stacklok/tap. Instead, we rely on brew's automation to catch the new release of the minder CLI and updates its entry in the homebrew-core repo. Currently this happens every 3 hours.

Related: https://github.com/mindersec/minder/issues/4753

Change Type

Mark the type of change your PR introduces:

• [ ] Bug fix (resolves an issue without affecting existing features)
• [ ] Feature (adds new functionality without breaking changes)
• [ ] Breaking change (may impact existing functionalities or require documentation updates)
• [ ] Documentation (updates or additions to documentation)
• [x] Refactoring or test improvements (no bug fixes or new functionality)

Testing

Outline how the changes were tested, including steps to reproduce and any relevant configurations. Attach screenshots if helpful.

Review Checklist:

• [x] Reviewed my own code for quality and clarity.
• [ ] Added comments to complex or tricky code sections.
• [ ] Updated any affected documentation.
• [ ] Included tests that validate the fix or feature.
• [ ] Checked that related changes are merged.