pip install --use-feature=2020-resolver

Author: cclauss

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip setuptools six
-          python -m pip install pytest-cov -r requirements.txt
+          python -m pip install --use-feature=2020-resolver pytest-cov -r requirements.txt
       - name: Run tests
         run: pytest --doctest-modules --ignore=project_euler/ --cov-report=term-missing:skip-covered --cov=. .
       - if: ${{ success() }}