chore: relock pdm and use python version from pyproject.toml

Author: robtaylor

.github/workflows/main.yaml

@@ -32,8 +32,6 @@ jobs:
         uses: actions/checkout@v4
 
       - uses: actions/setup-python@v4
-        with:
-          python-version: '3.10'
 
       - name: Set up PDM
         uses: pdm-project/setup-pdm@v4