Mark extensions/v1beta1 Ingress deprecated

Author: liggitt

api/openapi-spec/swagger.json

@@ -541,6 +541,7 @@ type DaemonSetList struct {
 // endpoints defined by a backend. An Ingress can be configured to give services
 // externally-reachable urls, load balance traffic, terminate SSL, offer name
 // based virtual hosting etc.
+// DEPRECATED - This group version of Ingress is deprecated by networking.k8s.io/v1beta1 Ingress. See the release notes for more information.
 type Ingress struct {
 	metav1.TypeMeta `json:",inline"`
 	// Standard object's metadata.