chore(deps): update postgres-cluster docker tag to v7.15.0

clusters/cl01tl/helm/matrix-synapse/Chart.lock

@@ -19,7 +19,7 @@ dependencies:
   version: 3.3.1
 - name: postgres-cluster
   repository: oci://harbor.alexlebens.net/helm-charts
-  version: 7.14.0
+  version: 7.15.0
 - name: valkey
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 0.8.0
@@ -38,5 +38,5 @@ dependencies:
 - name: volsync-target
   repository: oci://harbor.alexlebens.net/helm-charts
   version: 2.0.0
-digest: sha256:280828df104118ddbe6b18397faa5b08af9d4012dfbd257bc205018834dca006
-generated: "2026-05-18T20:33:28.387868-05:00"
+digest: sha256:d485d7a3232636f4a0c248ac7d80ba4e32f68da9381cbfa039ca228993fafd19
+generated: "2026-05-19T16:08:25.549214673Z"