remove submodules

Author: Jonathan Kliem

.github/workflows/main.yml

@@ -23,9 +23,6 @@ jobs:
         steps:
         - name: Set up the repository
           uses: actions/checkout@v2
-          with:
-              submodules: recursive
-              fetch-depth: 0
         - name: Set up Python ${{ matrix.python-version }}
           uses: actions/setup-python@v2
           with: