Replace k8s.gcr.io references with registry.k8s.io (#1144)

* Replace k8s.gcr.io references with registry.k8s.io

Replace k8s.gcr.io references with registry.k8s.io

* Update release.md

* Update release.md

Author: asa3311

Makefile

@@ -48,7 +48,7 @@ SETUP_ENVTEST := $(TOOLS_BIN_DIR)/setup-envtest
 STAGING_REGISTRY ?= gcr.io/k8s-staging-capi-ibmcloud
 STAGING_BUCKET ?= artifacts.k8s-staging-capi-ibmcloud.appspot.com
 BUCKET ?= $(STAGING_BUCKET)
-PROD_REGISTRY := k8s.gcr.io/capi-ibmcloud
+PROD_REGISTRY := registry.k8s.io/capi-ibmcloud
 REGISTRY ?= $(STAGING_REGISTRY)
 RELEASE_TAG ?= $(shell git describe --abbrev=0 2>/dev/null)
 PULL_BASE_REF ?= $(RELEASE_TAG) # PULL_BASE_REF will be provided by Prow