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/api/errors/OWNERS

@@ -23,4 +23,3 @@ reviewers:
 - krousey
 - cjcullen
 - david-mcmahon
-- goltermann