Run CI using new macos-15-intel runner

Author: marcprux

.github/workflows/ci.yml

@@ -15,5 +15,5 @@ jobs:
   call-workflow:
     uses: skiptools/actions/.github/workflows/skip-framework.yml@v1
     with:
-      runs-on: "['macos-13', 'ubuntu-24.04']"
+      runs-on: "['macos-15-intel', 'ubuntu-24.04']"