Simplify the version definitions and add a new definition for 1.1

[phausler]

The existing definitions for the versions was lifted directly from Swift-Foundation and was overly complex for AsyncAlgorithms. This simplifies it and introduces a new version id of 1.1 defined as macOS 15.0, iOS 18.0, tvOS 18.0, watchOS 11.0, visionOS 2.0 *.

[stefanomondino]

Hi @phausler, is there anything that can be done to lower the minimum required version?
I was eager to try (by targeting main) the new .share() algorithm that just got merged, only to discover that I won't be able to use it in my iOS 16.0+ app because of this requirement.

[stefanomondino]

Nevermind, I just saw that the locking mechanism used to implement share() is a iOS 18+ API.

[phausler]

@stefanomondino that is as far back as it can be deployed for a few reasons; locking just being one of them, the other issue is that some of the isolation APIs are required to be swift 6.2; I really tried to get it back to 6.0 but sadly that ends up causing both compile time and runtime issues.

[pyrtsa]

What does Swift 6.2 and 6.0 have to do with platform version ranges? Why can't this be deployed back to iOS 16 or even lower?

[phausler]

the swift versions are tied to availability of specific APIs which are tied to specific releases for Apple platforms. e.g. withTaskPriorityEscalationHandler is only available given a specific OS version.