Update postgres-cluster Docker tag to v6.16.1 (#2237)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [postgres-cluster](https://github.com/cloudnative-pg/cloudnative-pg) | patch | `6.16.0` -> `6.16.1` |

---

### 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.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi41LjAiLCJ1cGRhdGVkSW5WZXIiOiI0Mi41LjAiLCJ0YXJnZXRCcmFuY2giOiJtYWluIiwibGFiZWxzIjpbImF1dG9tZXJnZSIsImltYWdlIl19-->

Reviewed-on: #2237
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/helm/grafana-operator/Chart.lock

@@ -4,6 +4,6 @@ dependencies:
   version: v5.20.0
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 6.16.0
-digest: sha256:d70b284b771af610116564e5f47d72415ab0d3520ecb552159ee8dc8acd2ab46
-generated: "2025-12-01T19:55:46.485062-06:00"
+  version: 6.16.1
+digest: sha256:3bd7096e4401df5818733b3e0b08f281c12af9b54a272fbe3e753b2616d725dd
+generated: "2025-12-04T00:01:28.278027037Z"