Fix mac CI configuration

Author: jgraham

.github/workflows/python.yml

@@ -108,9 +108,7 @@ jobs:
     strategy:
       matrix:
         platform:
-          - runner: macos-13
-            target: x86_64
-          - runner: macos-14
+          - runner: macos-15
             target: aarch64
     steps:
       - uses: actions/checkout@v4