code: func (dc *DeploymentController) updateDeploymentAndClearRollbackTo(d *apps.Deployment) error {
  	klog.V(4).Infof("Cleans up rollbackTo of deployment %q", d.Name)
  	setRollbackTo(d, nil)
  	_, err := dc.client.AppsV1().Deployments(d.Namespace).Update(d)
  	return err
  }
docs: // updateDeploymentAndClearRollbackTo sets .spec.rollbackTo to nil and update the input deployment
  // It is assumed that the caller will have updated the deployment template appropriately (in case
  // we want to rollback).