do I need to say more?
There have been a lot of posts about this. L&L have explained many times why iCloud sync’ing hasn’t been possible to date. In a recent post on the iOS forum Keith has intimated that he has some hopes that there might be changes at the iCloud end, but it’s not clear to me if that is only in terms of the Files.app on iOS devices. Here’s the link:
https://forum.literatureandlatte.com/t/ios-11-support-of-files-app/37322/13
Otherwise just do a search for “iCloud” in these forums, and you’ll find plenty of mentions.
Mark
Do I need to reply? 
Not to me!
Mark
Meanwhile, since you’re talking about macOS, put your project in your iCloud Drive folder if you prefer that service. That’s what it is there for. The premise of this technology was in the first place to do away with the concept of ever having to write in to a developer and ask for them to specifically support some private interface in order to make sync work.
Why not just use CloudKit. Other apps seem to have no trouble syncing packages (RTFDs etc)…