code: func (autoscalerStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Object) field.ErrorList {
  	return validation.ValidateHorizontalPodAutoscalerUpdate(obj.(*autoscaling.HorizontalPodAutoscaler), old.(*autoscaling.HorizontalPodAutoscaler))
  }
docs: // ValidateUpdate is the default update validation for an end user.