ci: update macOS runner from macos-13 to macos-15

macos-13 runner is being deprecated on December 4th, 2025.
Update to test on macos-14 and macos-15 (both ARM runners).

Author: Hiroshiba

.github/workflows/test.yml

@@ -19,8 +19,8 @@ jobs:
         include:
           - os: windows-2022
           - os: windows-2025
-          - os: macos-13
           - os: macos-14
+          - os: macos-15
           - os: ubuntu-22.04
           - os: ubuntu-24.04
     runs-on: ${{ matrix.os }}