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/gatus/Chart.lock

@@ -4,9 +4,9 @@ dependencies:
   version: 1.5.0
 - 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:c0c46db33b89b7a53dd512d19d07623a1eaafcc93668f0afacbb8d8c56d71e47
-generated: "2026-03-06T01:07:17.642671539Z"
+digest: sha256:2fe7c088e99a11e0c6dd09fe48bb1e292eb58e22d9f8ff681bb6c6790945d54e
+generated: "2026-03-11T22:56:56.957400817Z"