code: func (auditSinkStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Object) field.ErrorList {
  	validationErrorList := validation.ValidateAuditSink(obj.(*audit.AuditSink))
  	updateErrorList := validation.ValidateAuditSinkUpdate(obj.(*audit.AuditSink), old.(*audit.AuditSink))
  	return append(validationErrorList, updateErrorList...)
  }
docs: // ValidateUpdate is the default update validation for an end user.