ci: Fix regression from pytest 8.4

Author: enwask

pytest.ini

@@ -3,4 +3,3 @@ python_files = test_*.py *_example.py example_*.py
 addopts = --durations=20 --maxfail=5
 filterwarnings =
     ignore::pytest.PytestCacheWarning
-    ignore::pytest.PytestReturnNotNoneWarning

requirements-testing.txt

@@ -1,8 +1,8 @@
-pytest>=7.2,<9.0
+pytest>=7.2,<8.5
 pytest-runner<6.0.2
 pytest-cov<6.1.2
 flake8-pyproject>=1.2.3,<1.2.4
 nbval<0.11.1
 scipy<1.15.3
 pooch<1.8.3
-click<9.0
+click<9.0