Disabling test build for Python 3.7 on OS X since arm64 is no longer supported on GitHub for Python 3.7

Author: twwildey

.github/workflows/ci.yml

@@ -20,6 +20,8 @@ jobs:
         exclude:
           - os: macos-latest
             python-version:  "pypy3.9"
+          - os: macos-latest
+            python-version:  "3.7"
           - os: windows-latest
             python-version:  "pypy3.9"
     runs-on: ${{ matrix.os }}