chore(deps): update alpine docker tag to v3.18

This MR contains the following updates:

Package	Type	Update	Change
alpine	final	minor	3.17 -> 3.18
alpine	stage	minor	3.17 -> 3.18

---

Configuration

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

🚦 Automerge: Disabled due to failing status checks.

♻ Rebasing: Whenever MR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this MR and you won't be reminded about these updates again.

---

• If you want to rebase/retry this MR, click this checkbox.

---

This MR has been generated by Renovate Bot.