Move Stack on to GHC 9.4.7

[mpilgrem]

LTS Haskell 21.12 was published on 2023-09-14.

See also #6237.

[mpilgrem]

@benz0li, do you have Docker images for Alpine Linux and GHC 9.4.7? There is still no 'official' Alpine Linux/AArch64, but the official Alpine Linux/X86_64 (dynamically linked) is, I think, a working version. I am not sure if that changes anything.

[benz0li]

@benz0li, do you have Docker images for Alpine Linux and GHC 9.4.7?

Yes. There is: See https://gitlab.b-data.ch/ghc/ghc-musl/container_registry/381?orderBy=NAME&sort=asc&search[]=9.4.7&search[]=

Available HLS versions: See https://gitlab.b-data.ch/ghc/ghc-musl/container_registry/495

[benz0li]

Should you update stack.yaml to GHC 9.4.7, you may set "HLS_VERSION": "2.2.0.0" in .devcontainer/devcontainer.json.

– #6237 (comment)