Clone submodules in CI

Signed-off-by: James Hamlin <jfhamlin@gmail.com>

Author: jfhamlin

.github/workflows/ci.yml

@@ -14,6 +14,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
+      with:
+        submodules: recursive
     - uses: cachix/install-nix-action@v19
       with:
         nix_path: nixpkgs=channel:nixos-unstable