// is considered to match if either object matches the selector. A null
  // object (oldObject in the case of create, or newObject in the case of
  // delete) or an object that cannot have labels (like a
  // DeploymentRollback or a PodProxyOptions object) is not considered to
  // match.
  // Use the object selector only if the webhook is opt-in, because end
  // users may skip the admission webhook by setting the labels.