buildcheck: Require python 3.10

The latest rewrite introduced language features from python 3.10
Adjust the GitHub actions test to use 3.10 so that it does not fail.

.github/workflows/buildcheck.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v1
         with:
-          python-version: 3.8
+          python-version: 3.10.5
 
       - name: Install dependencies
         run: |