title: Get object notification for Google firestore using pub/sub
body: <p>I am aware that we can publish a message to a pubsub topic when a file gets uploaded/modified in cloud Firestore using <strong>cloud functions</strong>.</p>
  
  <p>Is there a similar way that this can we done without using Cloud Functions, like as we do it for gcs with,
  <strong>"gsutil notification create -t [pubsub_TOPIC_NAME] -f json -e OBJECT_FINALIZE gs://[BUCKET_NAME]"</strong>. So that whenever a file get uploaded/modified my Subscriber will get notified.</p>
  
  <p>Any help is appreciated!!!</p>