Update k8s dependency version to 1.21

Signed-off-by: xinyanwu409 <wxinyan@vmware>

vendor/k8s.io/api/policy/v1/doc.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// +k8s:deepcopy-gen=package
+// +k8s:protobuf-gen=package
+// +k8s:openapi-gen=true
+
+// Package policy is for any kind of policy object.  Suitable examples, even if
+// they aren't all here, are PodDisruptionBudget, PodSecurityPolicy,
+// NetworkPolicy, etc.
+package v1 // import "k8s.io/api/policy/v1"