[skip-release] Update github-actions (major)

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
docker/build-push-action	action	major	v6 → v7
docker/login-action	action	major	v3 → v4
docker/setup-buildx-action	action	major	v3 → v4

---

Release Notes

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

v7

Compare Source

docker/login-action (docker/login-action)

v4

Compare Source

docker/setup-buildx-action (docker/setup-buildx-action)

v4

Compare Source

---

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 is behind base branch, or you tick the rebase/retry checkbox.

👻 Immortal: This PR will be recreated if closed unmerged. Get config help if that's undesired.

---

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

---

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