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/util/diff/diff.go

@@ -19,6 +19,7 @@ package diff
 import (
 	"bytes"
 	"fmt"
+	"reflect"
 	"strings"
 	"text/tabwriter"
 
@@ -116,3 +117,41 @@ func ObjectGoPrintSideBySide(a, b interface{}) string {
 	w.Flush()
 	return buf.String()
 }
+
+// IgnoreUnset is an option that ignores fields that are unset on the right
+// hand side of a comparison. This is useful in testing to assert that an
+// object is a derivative.
+func IgnoreUnset() cmp.Option {
+	return cmp.Options{
+		// ignore unset fields in v2
+		cmp.FilterPath(func(path cmp.Path) bool {
+			_, v2 := path.Last().Values()
+			switch v2.Kind() {
+			case reflect.Slice, reflect.Map:
+				if v2.IsNil() || v2.Len() == 0 {
+					return true
+				}
+			case reflect.String:
+				if v2.Len() == 0 {
+					return true
+				}
+			case reflect.Interface, reflect.Ptr:
+				if v2.IsNil() {
+					return true
+				}
+			}
+			return false
+		}, cmp.Ignore()),
+		// ignore map entries that aren't set in v2
+		cmp.FilterPath(func(path cmp.Path) bool {
+			switch i := path.Last().(type) {
+			case cmp.MapIndex:
+				if _, v2 := i.Values(); !v2.IsValid() {
+					fmt.Println("E")
+					return true
+				}
+			}
+			return false
+		}, cmp.Ignore()),
+	}
+}