Checkout submodules in testing workflow

Author: yguclu

.github/workflows/testing.yml

@@ -40,7 +40,9 @@ jobs:
       OMP_NUM_THREADS: 2
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
+        with:
+          submodules: true
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5