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/kube-openapi/pkg/generators/rules/OWNERS

@@ -0,0 +1,4 @@
+reviewers:
+- roycaihw
+approvers:
+- roycaihw