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/deepcopy-gen/args/args.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2016 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"
+
+	"github.com/spf13/pflag"
+	"k8s.io/gengo/args"
+	"k8s.io/gengo/examples/deepcopy-gen/generators"
+)
+
+// CustomArgs is used by the gengo framework to pass args specific to this generator.
+type CustomArgs generators.CustomArgs
+
+// NewDefaults returns default arguments for the generator.
+func NewDefaults() (*args.GeneratorArgs, *CustomArgs) {
+	genericArgs := args.Default().WithoutDefaultFlagParsing()
+	customArgs := &CustomArgs{}
+	genericArgs.CustomArgs = (*generators.CustomArgs)(customArgs) // convert to upstream type to make type-casts work there
+	genericArgs.OutputFileBaseName = "deepcopy_generated"
+	return genericArgs, customArgs
+}
+
+// AddFlags add the generator flags to the flag set.
+func (ca *CustomArgs) AddFlags(fs *pflag.FlagSet) {
+	pflag.CommandLine.StringSliceVar(&ca.BoundingDirs, "bounding-dirs", ca.BoundingDirs,
+		"Comma-separated list of import paths which bound the types for which deep-copies will be generated.")
+}
+
+// Validate checks the given arguments.
+func Validate(genericArgs *args.GeneratorArgs) error {
+	_ = genericArgs.CustomArgs.(*generators.CustomArgs)
+
+	if len(genericArgs.OutputFileBaseName) == 0 {
+		return fmt.Errorf("output file base name cannot be empty")
+	}
+
+	return nil
+}