ci: add pytest-asyncio to publish.yml test step

The publish.yml test step is a duplicate of ci.yml but with its own
dependency list. It was missing pytest-asyncio, so the 11 new async
tests added in 0.2.1 failed the publish gate on that commit and
blocked the PyPI upload.

ci.yml was updated in the same PR; publish.yml was missed.

Small cherry-pick direct to main to unblock re-tagging v0.2.1.

Author: Delega Bot

.github/workflows/publish.yml

@@ -26,7 +26,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install -e ".[async]"
-          pip install pytest
+          pip install pytest pytest-asyncio
           pytest tests/ -v
 
   publish: