Checkout also the submodules using actions/checkout

Author: Alir3z4

.github/workflows/main.yml

@@ -45,6 +45,8 @@ jobs:
     steps:
       - name: Check out code
         uses: actions/checkout@v4
+        with:
+          submodules: true
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5