Replaced macos-15-intel from macos-13

Author: hsbt

.github/workflows/test.yml

@@ -37,7 +37,7 @@ jobs:
           - { os: windows-latest, ruby: ucrt }
           - { os: windows-latest, ruby: mingw }
           - { os: windows-latest, ruby: mswin }
-          - { os: macos-13, ruby: 2.5 }
+          - { os: macos-15-intel, ruby: 2.5 }
         exclude:
           # CRuby < 2.6 does not support macos-arm64
           - { os: macos-latest, ruby: 2.5 }