setup.cfg: pytest: specify testpaths, use tool:pytest

Author: blueyed

setup.cfg

@@ -5,8 +5,9 @@ verbose=2
 [bdist_wheel]
 universal=0
 
-[pytest]
+[tool:pytest]
 python_files=tests.py test_*.py *_tests.py
+testpaths = tests
 isort_ignore=
     opbeat/transport/asyncio.py
     opbeat/contrib/asyncio/client.py