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/informer-gen/args/args.go

@@ -0,0 +1,77 @@
+/*
+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 args
+
+import (
+	"fmt"
+	"path"
+
+	"github.com/spf13/pflag"
+	codegenutil "k8s.io/code-generator/pkg/util"
+	"k8s.io/gengo/args"
+)
+
+// CustomArgs is used by the gengo framework to pass args specific to this generator.
+type CustomArgs struct {
+	VersionedClientSetPackage string
+	InternalClientSetPackage  string
+	ListersPackage            string
+	SingleDirectory           bool
+}
+
+// NewDefaults returns default arguments for the generator.
+func NewDefaults() (*args.GeneratorArgs, *CustomArgs) {
+	genericArgs := args.Default().WithoutDefaultFlagParsing()
+	customArgs := &CustomArgs{
+		SingleDirectory: false,
+	}
+	genericArgs.CustomArgs = customArgs
+
+	if pkg := codegenutil.CurrentPackage(); len(pkg) != 0 {
+		genericArgs.OutputPackagePath = path.Join(pkg, "pkg/client/informers")
+		customArgs.VersionedClientSetPackage = path.Join(pkg, "pkg/client/clientset/versioned")
+		customArgs.InternalClientSetPackage = path.Join(pkg, "pkg/client/clientset/internalversion")
+		customArgs.ListersPackage = path.Join(pkg, "pkg/client/listers")
+	}
+
+	return genericArgs, customArgs
+}
+
+// AddFlags add the generator flags to the flag set.
+func (ca *CustomArgs) AddFlags(fs *pflag.FlagSet) {
+	fs.StringVar(&ca.InternalClientSetPackage, "internal-clientset-package", ca.InternalClientSetPackage, "the full package name for the internal clientset to use")
+	fs.StringVar(&ca.VersionedClientSetPackage, "versioned-clientset-package", ca.VersionedClientSetPackage, "the full package name for the versioned clientset to use")
+	fs.StringVar(&ca.ListersPackage, "listers-package", ca.ListersPackage, "the full package name for the listers to use")
+	fs.BoolVar(&ca.SingleDirectory, "single-directory", ca.SingleDirectory, "if true, omit the intermediate \"internalversion\" and \"externalversions\" subdirectories")
+}
+
+// Validate checks the given arguments.
+func Validate(genericArgs *args.GeneratorArgs) error {
+	customArgs := genericArgs.CustomArgs.(*CustomArgs)
+
+	if len(genericArgs.OutputPackagePath) == 0 {
+		return fmt.Errorf("output package cannot be empty")
+	}
+	if len(customArgs.VersionedClientSetPackage) == 0 {
+		return fmt.Errorf("versioned clientset package cannot be empty")
+	}
+	if len(customArgs.ListersPackage) == 0 {
+		return fmt.Errorf("listers package cannot be empty")
+	}
+
+	return nil
+}