use checkout

.github/workflows/build-docker.yml

@@ -22,11 +22,10 @@ jobs:
           - cdn-cs
           - gateway-offload
     steps:
+      - uses: actions/checkout@v6
       - uses: cachix/install-nix-action@v31
         with:
           nix_path: nixpkgs=channel:nixos-unstable
-      - name: Clone the server repository
-        run: git clone https://github.com/spacebarchat/server
       - name: Build the docker image
         run: nix build .#containers.x86_64-linux.docker.${{ matrix.package }}
         working-directory: server