Platform support for Stack 2.3 release

[Michael Snoyman]

Hi all,

For the upcoming 2.3 release of Stack, we're going to be reducing the number of platforms that we support with binary releases. The reason behind this is that we've been slowed down in our release process until now with issues trying to build binaries for less common platforms. In order to make sure we can address issues more quickly (like supporting new GHC versions), we're limiting support from the Stack team to:

* Linux 64-bit static

* MacOS

* Windows 64-bit

If others want to provide additional binaries, we will definitely be happy for the support. But since our CI system is currently able to produce these three bindists only, that's what we will be providing with the next release.