code: func setRollbackTo(d *apps.Deployment, rollbackTo *extensions.RollbackConfig) {
  	if rollbackTo == nil {
  		delete(d.Annotations, apps.DeprecatedRollbackTo)
  		return
  	}
  	if d.Annotations == nil {
  		d.Annotations = make(map[string]string)
  	}
  	d.Annotations[apps.DeprecatedRollbackTo] = strconv.FormatInt(rollbackTo.Revision, 10)
  }
docs: // TODO: Remove this when extensions/v1beta1 and apps/v1beta1 Deployment are dropped.