chore(deps): update postgres-cluster docker tag to v7.8.0 (#4278)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [postgres-cluster](https://github.com/cloudnative-pg/cloudnative-pg) | minor | `7.7.0` → `7.8.0` |

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Reviewed-on: #4278
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/helm/roundcube/Chart.lock

@@ -4,9 +4,9 @@ dependencies:
   version: 4.6.2
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 7.7.0
+  version: 7.8.0
 - name: volsync-target
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.7.0
-digest: sha256:34757980809efac266dd1efd7b837116ab593e71348ae6bab4066eb70a846442
-generated: "2026-02-21T20:04:09.418049218Z"
+digest: sha256:c689cbefd15127b5d64ce7dc4b976f953519396f9bcd5c4e499b6070a5b59a34
+generated: "2026-02-27T18:20:03.781834962Z"