FreshOS Then Versions Save

• Bumps to Swift version to 5.6
• min supported versions:
  • iOS 14
  • MacOS 11
  • tvOS 14
  • watchOS 7

Updated for iOS15 🎉

• Fixes #70 annoying Xcode warning The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.2.99. Thanks @simonbromberg
• Fixes Xcode13/iOS15 build by renaming await by awaitPromise #72 Thanks @RocZhang9673

The project now follows the Swift package Manager conventions which simplifies package maintenance. Swift Package Manager is now the official way to integrate Then on all platforms. 🎉 Onwards ! ✨🥂

• Updates Package.swift

• Build with Xcode 11.3 & Swift 5.1.3

• Adds watchOS support, Thanks to @jos76 👏✨

• Updates for Xcode 11 & Swift 5.1
• Renames framework from then to Then to comply to standards. thanks @MoveUpwardsDev 👍

Adds Swift 5 support courtesy of @bernardowilson 🎉