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/grafana-operator/Chart.lock

@@ -4,12 +4,12 @@ dependencies:
   version: 5.22.0
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 7.7.0
+  version: 7.8.0
 - name: redis-replication
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 1.0.4
 - name: redis-replication
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 1.0.4
-digest: sha256:ef0a64bd24d9c0d5e861fc949c173fecaaf418627b2bc64973547a9d577aa5cf
-generated: "2026-02-24T19:40:11.951103549Z"
+digest: sha256:38cb44dab5c7e678ff6eba7a3b57bdae94191eecf055bd4ee3feb26853ef07ff
+generated: "2026-02-27T18:16:10.426333246Z"