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/google.golang.org/grpc/codes/codes.go

@@ -132,7 +132,8 @@ const (
 
 	// Unavailable indicates the service is currently unavailable.
 	// This is a most likely a transient condition and may be corrected
-	// by retrying with a backoff.
+	// by retrying with a backoff. Note that it is not always safe to retry
+	// non-idempotent operations.
 	//
 	// See litmus test above for deciding between FailedPrecondition,
 	// Aborted, and Unavailable.