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/client-gen/path/path.go

@@ -0,0 +1,31 @@
+/*
+Copyright 2017 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.
+*/
+
+package path
+
+import "strings"
+
+// Vendorless removes the longest match of "*/vendor/" from the front of p.
+// It is useful if a package locates in vendor/, e.g.,
+// k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/apis/meta/v1, because gengo
+// indexes the package with its import path, e.g.,
+// k8s.io/apimachinery/pkg/apis/meta/v1,
+func Vendorless(p string) string {
+	if pos := strings.LastIndex(p, "/vendor/"); pos != -1 {
+		return p[pos+len("/vendor/"):]
+	}
+	return p
+}