gitlab-ci: Use ghc 9.2.8 for generate_jobs_metadata

Nix can't find ghc 9.2.4 for some reason, resulting in the lint-ci-config job failing

Metric Decrease:
    MultiLayerModulesTH_Make

Metric Increase:
    MultiLayerModulesTH_Make

.gitlab/generate_job_metadata

 #! /usr/bin/env nix-shell
-#!nix-shell -i bash -p cabal-install "haskell.packages.ghc924.ghcWithPackages (pkgs: with pkgs; [aeson])" git jq
+#!nix-shell -i bash -p cabal-install "haskell.packages.ghc928.ghcWithPackages (pkgs: with pkgs; [aeson])" git jq
 
 cd "$(dirname "${BASH_SOURCE[0]}")"
 cabal run gen_ci -- metadata jobs-metadata.json