I wrote it. I'm just trying to make some useful software. It's Windows-only, sorry. It's open-source, so you can see there's nothing funky going on. It just figures out how to call Butler with the correct parameters.
Check it out: https://walkerb.itch.io/gamepusher . It also uploads to Steam and Oculus, if you're using either of those stores.
If you run into any issues, post here and I'll see what's up.