Bump python version in CI

Author: dstansby

.github/workflows/main.yaml

@@ -24,7 +24,7 @@ jobs:
           persist-credentials: false
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
       - name: Install dependencies
         run: |
           sudo apt update