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/outline/Chart.lock

@@ -7,12 +7,12 @@ dependencies:
   version: 2.4.0
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 7.8.0
+  version: 7.9.1
 - name: valkey
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.4.0
 - name: volsync-target
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.8.0
-digest: sha256:e1f1a6ebdee3146e028c4df1762a4c60c1e62733a91e54d615190f8138be117d
-generated: "2026-03-11T16:37:32.297394-05:00"
+digest: sha256:1f2e4e46e3ae2985ff3e7708c7d75a36f506f0402e02921d95f797ea0403db93
+generated: "2026-03-11T23:00:00.871137498Z"