Update haproxy Docker tag to v2.9

[balena-renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
haproxy	final	minor	2.8-alpine -> 2.9-alpine

---

Configuration

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

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, 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 Renovate Bot.