This would be better in Help Wanted or Offered, and please see the rules of this category where it says not to advertise your Discord server.
Viewing post in The Internet Builds a Game (Join Us)
But I don't want any help, and I'm not promoting my Discord server either. It's just a general comment.
I only mention the Discord server because it’s the only way to communicate with a larger group of people. If it were possible, I’d coordinate this through Itch, but unfortunately that’s not an option. I’m not doing this to promote myself, it’s simply the best option I could come up with. So this isn’t an advertisement.
You’re explicitly inviting people to a collaborative project. They could for example reply to your topic. Or you could make a placeholder page, where you could even advertise the Discord server, or more simply host a community forum. Or this could happen on a software forge, since you mentioned Git.