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/vaultwarden/Chart.lock

@@ -7,9 +7,9 @@ dependencies:
   version: 2.4.0
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 7.8.0
+  version: 7.9.1
 - name: volsync-target
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.8.0
-digest: sha256:5d53feec286aa922cb048e96ce6a8cfd595f6aa05248a868db773fb06cb0165d
-generated: "2026-03-09T22:06:29.256670152Z"
+digest: sha256:1d6f670bfe76dbc3d59a2ff762cb5536be8d1f5ce0ed12b44bd9792076607bed
+generated: "2026-03-11T23:03:57.367242959Z"