update workflow to use Python 3.10 instead of Python 3.12

Author: todbot

.github/workflows/macos.yml

@@ -33,7 +33,7 @@ jobs:
         run: echo "no prereqs to set up"
 
       - name: Setup Python
-      - uses: actions/setup-python@v5
+        uses: actions/setup-python@v5
         with:
           python-version: "3.10"