ci: update macOS test matrix to include macos-15-intel

Author: Zxilly

.github/workflows/built-tests.yml

@@ -151,7 +151,7 @@ jobs:
     continue-on-error: true
     strategy:
       matrix:
-        os: [ ubuntu-24.04, ubuntu-24.04-arm, windows-latest, macos-13, macos-14 ]
+        os: [ ubuntu-24.04, ubuntu-24.04-arm, windows-latest, macos-15-intel, macos-14 ]
     steps:
       - name: Merge
         uses: actions/upload-artifact/merge@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0