code: func (cronJobStrategy) ValidateUpdate(ctx context.Context, obj, old runtime.Object) field.ErrorList {
  	newCronJob := obj.(*batch.CronJob)
  	oldCronJob := old.(*batch.CronJob)
  	allErrs := validation.ValidateCronJobUpdate(newCronJob, oldCronJob)
  	allErrs = append(allErrs, corevalidation.ValidateConditionalPodTemplate(
  		&newCronJob.Spec.JobTemplate.Spec.Template,
  		&oldCronJob.Spec.JobTemplate.Spec.Template,
  		field.NewPath("spec.jobTemplate.spec.template"))...)
  	return allErrs
  }
docs: // ValidateUpdate is the default update validation for an end user.