fix building of wheels

.github/workflows/building-conda.yml

@@ -34,6 +34,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+        with:
+          submodules: 'recursive'
+
       - name: Set up Conda for Python ${{ matrix.python-version }}
         uses: conda-incubator/setup-miniconda@v2
         with:

.github/workflows/building.yml

@@ -34,6 +34,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+        with:
+          submodules: 'recursive'
+
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v2
         with: