Fix MacOS CI builds #117
Description
From #115 (comment)
The CI issue is caused by macos-latest now pointing to macos-14 which is arm instead of intel. The fix is probably to use actions/setup-python@v4 instead of actions/setup-python@v1, set macos-intel and macos-arm as macos-12 and macos-14 respectively, and disable 3.8 for macos-arm. See temporalio/sdk-python#506.