[Pitch] Bringing Swiftly to Windows

Motivation Installing Swift on Windows today means downloading an installer from swift.org and running it. That works for one toolchain, but anyone who needs a second version, say to test a package against 6.1 and 6.2, or to follow a project’s .swift-version file, ends up uninstalling and reinstalling by hand. On Linux and macOS, swiftly solves this with swiftly install and swiftly use. I also remember how painful Linux setup was before it existed. Benefits to Community This project makes it ea...