chore(deps): update docker/build-push-action action to v6

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
docker/build-push-action	action	major	v4 -> v6

---

Release Notes

docker/build-push-action (docker/build-push-action)

### [`v6`](https://togithub.com/docker/build-push-action/compare/v5...v6) [Compare Source](https://togithub.com/docker/build-push-action/compare/v5...v6) ### [`v5`](https://togithub.com/docker/build-push-action/compare/v4...v5) [Compare Source](https://togithub.com/docker/build-push-action/compare/v4...v5)

---

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 was generated by Mend Renovate. View the repository job log.