Update redhat-actions/push-to-registry action to v2.8

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
redhat-actions/push-to-registry	action	minor	v2.7 -> v2.8

---

Release Notes

redhat-actions/push-to-registry (redhat-actions/push-to-registry)

### [`v2.8`](https://togithub.com/redhat-actions/push-to-registry/blob/HEAD/CHANGELOG.md#v28) [Compare Source](https://togithub.com/redhat-actions/push-to-registry/compare/v2.7...v2.8) - Update action to run on Node20. https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by Mend Renovate. View repository job log here.