py-test-asyncio: updated to 0.18.3

0.18.3 (22-03-25)
=================
- Adds `pytest-trio <https://pypi.org/project/pytest-trio/>`_ to the test dependencies
- Fixes a bug that caused pytest-asyncio to try to set up async pytest_trio fixtures in strict mode.

0.18.2 (22-03-03)
=================
- Fix asyncio auto mode not marking static methods.
- Fix a compatibility issue with Hypothesis 6.39.0.

(adam)