chore(deps): update bitnami/postgres-exporter docker tag to v0.15.0-debian-12-r39

[renovate-bot]

This PR contains the following updates:

Package	Update	Change
bitnami/postgres-exporter (source)	patch	0.15.0-debian-12-r38 -> 0.15.0-debian-12-r39

---

[!WARNING] Some dependencies could not be looked up. Check the Dependency Dashboard for more information.

---

Configuration

📅 Schedule: Branch creation - "before 4am on Monday" (UTC), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ 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.