Try Python 3.12 for CI build as well.

.github/workflows/sdrangel.yml

@@ -41,6 +41,9 @@ jobs:
           echo github.event_name: ${{ github.event_name }}
           echo github.ref: ${{ github.ref }}
           echo github.workspace: ${{ github.workspace }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
       - name: Install basic dependencies on Windows
         if: startsWith(matrix.config.os, 'windows')
         run: |