Upate to work with the latest Iris

[co-dan]

ported with the help of codex

[co-dan]

i think we will need to update the .nix file somehow too.
do you know what has to be done for that @Kaptch ?

[Kaptch]

Thanks!
Yep, I think the diff below should fix it:
nixpkgs.url = github:NixOS/nixpkgs/nixos-24.11; to nixpkgs.url = github:NixOS/nixpkgs/nixos-26.05;
and

coq = pkgs.coq_8_20;
coqPkgs = pkgs.coqPackages_8_20;

to

coq = pkgs.rocq-core_9_2;
coqPkgs = pkgs.rocqPackages_9_2;

I can take a look. Probably, we should also update ubuntu-based CI.