use staging repo for rc1

Change-Id: Ia8bcca03b64e92e62992f30c36ed60057d4dd83b

Author: mattcary

deploy/kubernetes/images/prow-gke-release-staging-rc-master/image.yaml

@@ -51,6 +51,6 @@ kind: ImageTagTransformer
 metadata:
   name: imagetag-csi-gce-driver-prow-rc
 imageTag:
-  name: k8s.gcr.io/cloud-provider-gcp/gcp-compute-persistent-disk-csi-driver
+  name: gcr.io/k8s-staging-cloud-provider-gcp/gcp-compute-persistent-disk-csi-driver
   newTag: "v1.3.2-rc1"
 ---