Update Kubegres image registry

The previous registry has been completely dismissed.

Signed-off-by: Luigi De Matteis <ldematteis123@gmail.com>

Author: luigidematteis

deploy/postgres-operator/kubegres-operator.yaml

@@ -88,7 +88,7 @@ spec:
         - --upstream=http://127.0.0.1:8080/
         - --logtostderr=true
         - --v=0
-        image: gcr.io/kubebuilder/kube-rbac-proxy:v0.14.1
+        image: registry.k8s.io/kubebuilder/kube-rbac-proxy:v0.14.1
         name: kube-rbac-proxy
         ports:
         - containerPort: 8443