code: func (actor Actor) UpdateApplication(app Application) (Application, Warnings, error) {
  	ccApp := ccv3.Application{
  		GUID:                app.GUID,
  		StackName:           app.StackName,
  		LifecycleType:       app.LifecycleType,
  		LifecycleBuildpacks: app.LifecycleBuildpacks,
  	}
  
  	updatedApp, warnings, err := actor.CloudControllerClient.UpdateApplication(ccApp)
  	if err != nil {
  		return Application{}, Warnings(warnings), err
  	}
  
  	return actor.convertCCToActorApplication(updatedApp), Warnings(warnings), nil
  }
docs: // UpdateApplication updates the buildpacks on an application