code: func (jobStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Object) field.ErrorList {
  	job := obj.(*batch.Job)
  	oldJob := old.(*batch.Job)
  	validationErrorList := validation.ValidateJob(job)
  	updateErrorList := validation.ValidateJobUpdate(job, oldJob)
  	updateErrorList = append(updateErrorList, corevalidation.ValidateConditionalPodTemplate(&job.Spec.Template, &oldJob.Spec.Template, field.NewPath("spec.template"))...)
  	return append(validationErrorList, updateErrorList...)
  }
docs: // ValidateUpdate is the default update validation for an end user.