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/apimachinery/pkg/runtime/schema/group_version.go

@@ -191,6 +191,11 @@ func (gv GroupVersion) String() string {
 	return gv.Version
 }
 
+// Identifier implements runtime.GroupVersioner interface.
+func (gv GroupVersion) Identifier() string {
+	return gv.String()
+}
+
 // KindForGroupVersionKinds identifies the preferred GroupVersionKind out of a list. It returns ok false
 // if none of the options match the group. It prefers a match to group and version over just group.
 // TODO: Move GroupVersion to a package under pkg/runtime, since it's used by scheme.
@@ -246,6 +251,15 @@ func (gv GroupVersion) WithResource(resource string) GroupVersionResource {
 //   in fewer places.
 type GroupVersions []GroupVersion
 
+// Identifier implements runtime.GroupVersioner interface.
+func (gv GroupVersions) Identifier() string {
+	groupVersions := make([]string, 0, len(gv))
+	for i := range gv {
+		groupVersions = append(groupVersions, gv[i].String())
+	}
+	return fmt.Sprintf("[%s]", strings.Join(groupVersions, ","))
+}
+
 // KindForGroupVersionKinds identifies the preferred GroupVersionKind out of a list. It returns ok false
 // if none of the options match the group.
 func (gvs GroupVersions) KindForGroupVersionKinds(kinds []GroupVersionKind) (GroupVersionKind, bool) {