remove macos-13 from our CI matrix because it is deprecated

Author: bhazelton

.github/workflows/macosx_windows_ci.yaml

@@ -32,9 +32,6 @@ jobs:
             os: windows-latest
           - env_name: pyuvdata_tests_mac_arm
             os: macos-latest
-          - env_name: pyuvdata_tests
-            os: macos-13
-            python-version: "3.12"
     steps:
       - uses: actions/checkout@main
         with: