Update docs to reflect official stack support for arm64

[kidq330]

https://hub.docker.com/_/haskell/ and the README both assure that stack+arm64 are not yet supported, but the issues they reference look to be all resolved. Is it time to update the docs to reflect this? Possibly with the info on the exact version that started offering official arm64 support?

[develop7]

Thank you for the heads-up! Will fix this as soon as I've got time, unless someone addresses this issue in a PR.

[benz0li]

@kidq330 You may be interested in GHC musl – unofficial and untested binary distributions of GHC on Alpine Linux/{x86_64,AArch64,RISC-V} (64-bit).

Including Stack. Also for Linux/RISC-V (64-bit).

Cross reference:

• https://gitlab.b-data.ch/commercialhaskell/stack/-/releases