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