ci: support Emacs 29.2

[panchoh]

Emacs 29.2¹ recently hit both nixos-unstable² and release-23.11³

¹ https://lists.gnu.org/archive/html/emacs-devel/2024-01/msg00666.html

² https://github.com/NixOS/nixpkgs/pull/281789 https://nixpk.gs/pr-tracker.html?pr=281789

³ https://github.com/NixOS/nixpkgs/pull/282259 https://nixpk.gs/pr-tracker.html?pr=282259

I hope I've understood correctly the purpose of both the var in the flake and the one in the workflow.

[panchoh]

(I've noticed that the test CI / lint-nix / nixpkgs-fmt fails, but that's to be expected, since flake.nix is not currently formatted following nixpkgs-fmt style).

[remi-gelinas]

Hey @panchoh! Sorry for the long wait on getting to this, we've transferred the repo over to nix-community to get some more maintaining help. We've rewritten some of the actions for releasing, and removed the redundant env var you pointed out, so you should be able to rebase on the latest trunk and just add 29.2 to the flake var to add support.

[remi-gelinas]

Just to add to this actually, I just split out the Emacs version list to allow CI to use it to trigger a lint/test change without making the flake source count as well. The new list is located at nix/emacs-versions.nix if you want to add 29.2.

[purcell]

Also there's 29.3 now too. 😁

[remi-gelinas]

I took the liberty of adding 29.2 and .3 in #26 - I'll close this out