Merge pull request #5197 from FelixSchwarz/pytest-warning

declare "allow_cache_wipe" marker in pytest.ini to avoid pytest warning

setup.cfg

@@ -1,5 +1,7 @@
 [tool:pytest]
 python_files = testsuite/*.py
+markers =
+    allow_cache_wipe
 
 [flake8]
 # please note that the values are adjusted so that they do not cause failures