This has been discussed fairly extensively in these forums. It would be worth doing a search using, say, the term “collaboration”. One thread you’ll turn up is this one: [url]On Line Version??], which is worth reading all the way through. In that thread, it’s pointed out that “serial collaboration” (read the thread for a definition) is already possible - and not necessarily using GitHub. But that’s perhaps not what you’re seeking. You may mean “parallel collaboration”.
One potentially limiting or complicating factor is that a Scrivener “file” isn’t in fact a file - it’s a folder containing possibly hundreds of files, all of which contribute to a single Scrivener “project”. Getting all those files to “work” together if being amended simultaneously in separate locations would increase the difficulty of “parallel collaboration”.