Stop enabling alpha runtimeclass API

Author: liggitt

cluster/gce/gci/configure-kubeapiserver.sh

@@ -264,9 +264,6 @@ function start-kube-apiserver {
   if [[ -n "${FEATURE_GATES:-}" ]]; then
     params+=" --feature-gates=${FEATURE_GATES}"
   fi
-  if [[ "${FEATURE_GATES:-}" =~ "RuntimeClass=true" ]]; then
-    params+=" --runtime-config=node.k8s.io/v1alpha1=true"
-  fi
   if [[ -n "${MASTER_ADVERTISE_ADDRESS:-}" ]]; then
     params+=" --advertise-address=${MASTER_ADVERTISE_ADDRESS}"
     if [[ -n "${PROXY_SSH_USER:-}" ]]; then