must have python 3.9

Author: lorenzwalthert

.github/workflows/pre-commit.yaml

@@ -32,7 +32,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v2
         with:
-          python-version: "3.8"
+          python-version: "3.9"
           architecture: "x64"
       - name: Run pre-commit
         uses: pre-commit/[email protected]