feat(workflows/eval): Use nix runners

.forgejo/workflows/eval.yaml

@@ -6,17 +6,10 @@ on:
 
 jobs:
   build_configs:
-    runs-on: debian-latest
+    runs-on: nix
     steps:
-      - name: Install applications
-        run: apt-get update && apt-get install sudo
-
       - uses: actions/checkout@v3
 
-      - uses: https://github.com/cachix/install-nix-action@v22
-        with:
-          nix_path: nixpkgs=channel:nixos-unstable
-
       - name: Build the nodes
         run: |
           # Enter the shell