Use Swift 6 and its new Concurrency Model

[lwouis]

I would like to migrate the project to Swift 6.

• It's unavoidable to migrate. Eventually version 5.8 will stop being supported. So we have a gun in our backs, and have to march forwards, regardless of what we want.
• This project uses a lot of concurrency. This is how we keep things performant. Keyboard handling, taking screenshots, etc. There are maybe a dozen different things done on separate threads or dispatch queues. Swift 6 model could help formalize things, and prevent races and misunderstandings.

Blocker: today I work on AltTab using AppCode. I can't imagine using XCode to work on it. I hate using XCode. Unfortunately, AppCode has been abandonned. So time is ticking. The current version doesn't understand Swift 6, so I can't migrate now. Fleet seems to support Swift, so that may be the future. In the meanwhile, the project doesn't run on Fleet for me, so it's a deadend at the moment.

[MolinDiscovery]

I really hope Fleet can work out. Your work is very much appreciated.