There are those email notification settings. Following alone should already keep you updated for important updates. And playing a game after a long pause, well, just visit the page. But the handling of the updates is manual. It's rare to have a game with an update function, and frankly, I would not trust indie devs to implement this - that's what the Itch app would be for.
New devlogs and updates from projects I follow
New uploads are added to something I bought or follow