label_sync/main.go
func rename(repo string, previous, wanted Label) Update {
	logrus.WithField("repo", repo).WithField("from", previous.Name).WithField("to", wanted.Name).Info("rename")
	return Update{Why: "rename", Current: &previous, Wanted: &wanted, repo: repo}
}
func rename(repo string, previous, wanted Label) Update {
	logrus.WithField("repo", repo).WithField("from", previous.Name).WithField("to", wanted.Name).Info("rename")
	return Update{Why: "rename", Current: &previous, Wanted: &wanted, repo: repo}
}
// Rename the label (will also update color)