UPSTREAM: <carry>: Updating kube-proxy-container image to be consistent with ART for 4.21

Reconciling with https://github.com/openshift/ocp-build-data/tree/4fbe3fab45239dc4be6f5d9d98a0bf36e0274ec9/images/kube-proxy.yml

Author: AOS Automation Release Team

.ci-operator.yaml

@@ -1,4 +1,4 @@
 build_root_image:
   name: release
   namespace: openshift
-  tag: rhel-9-release-golang-1.24-openshift-4.20
+  tag: rhel-9-release-golang-1.24-openshift-4.21

openshift-hack/images/kube-proxy/Dockerfile.rhel

@@ -1,11 +1,11 @@
-FROM registry.ci.openshift.org/ocp/builder:rhel-9-golang-1.24-openshift-4.20 AS builder
+FROM registry.ci.openshift.org/ocp/builder:rhel-9-golang-1.24-openshift-4.21 AS builder
 WORKDIR /go/src/k8s.io/kubernetes
 COPY . .
 RUN make WHAT='cmd/kube-proxy' && \
     mkdir -p /tmp/build && \
     cp /go/src/k8s.io/kubernetes/_output/local/bin/linux/$(go env GOARCH)/kube-proxy /tmp/build
 
-FROM registry.ci.openshift.org/ocp/4.20:base-rhel9
+FROM registry.ci.openshift.org/ocp/4.21:base-rhel9
 RUN INSTALL_PKGS="conntrack-tools iptables nftables" && \
     yum install -y --setopt=tsflags=nodocs $INSTALL_PKGS && \
     yum clean all && rm -rf /var/cache/*