. t Upgrade pytest-asyncio to latest

Unpinned pytest-asyncio.

Python 3.14 has a new warning triggered by this old pytest-asyncio:

```
pytest_asyncio\plugin.py:465: DeprecationWarning: 'asyncio.get_event_loop_policy' is deprecated and slated for removal in Python 3.16
```

Previously pytest-asyncio was pinned to an old version due to an incompatibility with PyCharm test runner, which appears to be fixed

Co-Authored-By: 4dsherwood <4dsherwood@users.noreply.github.com>
Co-Authored-By: Trillium Smith <trillium@trilliumsmith.com>
Co-Authored-By: Susan Fung <38925660+susanfung@users.noreply.github.com>

Author: 4 people

requirements.test.txt

@@ -3,7 +3,7 @@ numpy
 pylint
 
 pytest
-pytest-asyncio==0.21.1 # 0.23 has a bug 2023/12/3
+pytest-asyncio
 pytest-xdist
 PyYAML