ci: replace deprecated macos-13 runner (#656)

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ jobs:
       fail-fast: false
       matrix:
         # https://docs.github.com/en/actions/using-github-hosted-runners
-        os: [ubuntu-latest, windows-latest, macos-latest, macos-13]
+        os: [ubuntu-latest, windows-latest, macos-latest, macos-15-intel]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v5