Enable validation-gen on core/v1

This enables generation but does not activate the strategy calling of
declarative.

pkg/apis/core/v1/doc.go

@@ -18,6 +18,8 @@ limitations under the License.
 // +k8s:conversion-gen-external-types=k8s.io/api/core/v1
 // +k8s:defaulter-gen=TypeMeta
 // +k8s:defaulter-gen-input=k8s.io/api/core/v1
+// +k8s:validation-gen=TypeMeta
+// +k8s:validation-gen-input=k8s.io/api/core/v1
 
 // Package v1 is the v1 version of the API.
 package v1

pkg/apis/core/v1/zz_generated.validations.go

@@ -0,0 +1,34 @@
+//go:build !ignore_autogenerated
+// +build !ignore_autogenerated
+
+/*
+Copyright 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.
+*/
+
+// Code generated by validation-gen. DO NOT EDIT.
+
+package v1
+
+import (
+	runtime "k8s.io/apimachinery/pkg/runtime"
+)
+
+func init() { localSchemeBuilder.Register(RegisterValidations) }
+
+// RegisterValidations adds validation functions to the given scheme.
+// Public to allow building arbitrary schemes.
+func RegisterValidations(scheme *runtime.Scheme) error {
+	return nil
+}