chore: use submodules in ci

Author: not-matthias

.github/workflows/ci.yml

@@ -15,6 +15,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: true
       - name: Set up Python 3.11
         uses: actions/setup-python@v5
         with:
@@ -44,6 +46,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: true
       - uses: astral-sh/setup-uv@v4
         with:
           version: "0.5.20"