ci(postgres): Add renovate to update spilo image

infrastructure/base/postgres/release.yaml

@@ -40,6 +40,8 @@ data:
       default_memory_limit: 1Gi
       default_memory_request: 500Mi
     configGeneral:
+      # renovate: datasource=docker depName=ghcr.io/zalando/spilo-15
+      docker_image: ghcr.io/zalando/spilo-15:3.0-p1
       sidecars:
         - name: "exporter"
           # renovate: