Had to drop support for Swift 5.4/5.5 and macOS 5.6 jobs, see https://github.com/TokamakUI/Tokamak/pull/475#issuecomment-1092662828 for more details.
Linux builds and `codecov` job were updated to use nightly Swift, which have crashes reproducible in 5.6.0 release fixed.
Also applied a few formatting changes with the latest SwiftFormat.
* Ignore xcodeproj generated by SwiftPM
* Update to use official OpenCombine to avoid Xcode build error
* Use forked version with ObservableObject implementation
* Fix ambigious error
* Ignore SwiftPM edit mode package
* Update toolchain version
I’ve added two TextFields to the demo, which are supposed to have their values synced. Pressing enter in the second one will increment the commit counter.