1. update clientset, deepcopy using code-generator

2. add a dummy file tools.go to force "go mod vendor" to see
code-generator as dependencies
3. add a script to update CRD
4. add a README to document CRD updating steps
run go mod tidy
update README

vendor/k8s.io/code-generator/cmd/go-to-protobuf/main.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2015 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.
+*/
+
+// go-to-protobuf generates a Protobuf IDL from a Go struct, respecting any
+// existing IDL tags on the Go struct.
+package main
+
+import (
+	goflag "flag"
+
+	flag "github.com/spf13/pflag"
+	"k8s.io/code-generator/cmd/go-to-protobuf/protobuf"
+)
+
+var g = protobuf.New()
+
+func init() {
+	g.BindFlags(flag.CommandLine)
+	goflag.Set("logtostderr", "true")
+	flag.CommandLine.AddGoFlagSet(goflag.CommandLine)
+}
+
+func main() {
+	flag.Parse()
+	protobuf.Run(g)
+}