chore(deps): update postgres-cluster docker tag to v7.9.1 (#4639)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [postgres-cluster](https://github.com/cloudnative-pg/cloudnative-pg) | minor | `7.8.0` → `7.9.1` |

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Reviewed-on: #4639
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/helm/harbor/Chart.lock

@@ -4,9 +4,9 @@ dependencies:
   version: 1.18.2
 - name: postgres-cluster
   repository: https://gitea.alexlebens.net/api/packages/alexlebens/helm
-  version: 7.8.0
+  version: 7.9.1
 - name: valkey
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.4.0
-digest: sha256:ee8ed34cd53d8fa36497df28cba9cf16ef656250b0bc3ff6690fb958b22caf6f
-generated: "2026-03-09T23:07:20.650108569Z"
+digest: sha256:898f51eabee5959b9e7ebe90640cb915cb2dee446e6a6649a29499fecab8b6c7
+generated: "2026-03-11T22:58:00.955579445Z"