chore: Pin python version to fix aiohttp regression tests (#788)

Author: pimterry

.github/workflows/aiohttp.yml

@@ -43,7 +43,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
       with:
-        python-version: 3.x
+        python-version: 3.13
         cache: 'pip'
         cache-dependency-path: 'requirements/*.txt'
     - name: Provision the dev env