In my case its in the options:
Gog galacy: Left side are the games. There are two buttons: "play" and "more".
Click on "more": Then there are "options".
Click on them and you can choose for automatic updates.
But i must warn you: i just had an update, which did improve the speed of the game. But now the item menu is super bugged up to the point, that stuff can just vanish when trying to move it....
Yeah, I know about that. My question is whether or not Owlcat intends to use the tools available to push updates on GOG "instantly" like happens on Steam or whether to intend to just upload the files and wait for GOG staff to package them for deployment.
Judging by the thread on here about the MAC version, I'm guessing it's the latter (the patch was available on Steam for a long time before GOG). Where this becomes particularly annoying is weekends, because GOG doesn't work on weekends. So if a dev releases a patch on Thursday or Friday, GOG players probably won't get it until the next week.
This isn't a big deal for older games, but is on new releases. To be clear, this isn't GOG's fault. The developers have the tools available to them to publish their own patches on GOG just like Steam, but many seem to be choosing not to do so. I hate to punish GOG for this, but I don't want to purchase new releases that will be heavily patched on here unless the developer will put forth the effort to push those patches in a timely manner.