code: func (podTemplateStrategy) PrepareForUpdate(ctx context.Context, obj, old runtime.Object) {
  	newTemplate := obj.(*api.PodTemplate)
  	oldTemplate := old.(*api.PodTemplate)
  
  	pod.DropDisabledTemplateFields(&newTemplate.Template, &oldTemplate.Template)
  }
docs: // PrepareForUpdate clears fields that are not allowed to be set by end users on update.