Pin pytest to less than version 9 temporarily

Co-authored-by: RonnyPfannschmidt <156838+RonnyPfannschmidt@users.noreply.github.com>

Author: Copilot

.github/workflows/pythonapp.yml

@@ -57,7 +57,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -U setuptools setuptools_scm
-        pip install pytest
+        pip install "pytest<9"
     - uses: actions/download-artifact@v4
       with:
         name: dist