Test on macos-15

Author: pgleeson

.github/workflows/ci_versions.yml

@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
-        runs-on: [ubuntu-latest, macos-latest ]
+        runs-on: [ubuntu-latest, macos-latest, macos-15 ]
         exclude:
           - runs-on: macos-latest
             python-version: ["3.9"]