nix: Add git lfs

Author: zah

flake.nix

@@ -12,8 +12,8 @@
         let pkgs = import nixpkgs { inherit system; };
         in {
           default = pkgs.mkShell {
-            packages = with pkgs; [ ruby just ];
+            packages = with pkgs; [ ruby just git-lfs ];
           };
         });
     };
-}
+}