update CI to new macos runner

Author: nmwsharp

.github/workflows/test_macos.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: macos-13
+          - os: macos-15-intel
             arch: x64
           - os: macos-latest
             arch: arm64