ci-hotfix: use 3.9 wheel for upload

Author: btschwertfeger

.github/workflows/_build.yaml

@@ -72,7 +72,7 @@ jobs:
       - name: Store the distribution packages
         uses: actions/upload-artifact@v4
         # upload artifacts with the oldest supported version
-        if: runner.os == 'linux' && inputs.python-version == '3.8'
+        if: runner.os == 'linux' && inputs.python-version == '3.9'
         with:
           name: python-package-distributions
           path: dist/