Windows support in the CI.

.github/workflows/pyasdf.yml

@@ -28,7 +28,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install ruff black pytest
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        pip install -r requirements.txt
     - name: Lint with black
       run: |
         black --check .