As you can read there, you only get notified to update when there is a new milestone. If you were told to update after every commit, that would be several times a day.
When you notice a bug it’s always good to update first to check whether it was already fixed.
I also like Find what version of Discourse you're using as an explanation how you can check your exact version on GitHub. Of coure as an admin you don’t need the html view.