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/client-gen/OWNERS

@@ -0,0 +1,10 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+approvers:
+- lavalamp
+- wojtek-t
+- caesarxuchao
+reviewers:
+- lavalamp
+- wojtek-t
+- caesarxuchao