[ci] switch macos-13 to macos-15-intel due to the macOS-13 based runner images are being deprecated

Author: kunkundi

.github/workflows/build.yml

@@ -144,7 +144,7 @@ jobs:
       matrix:
         include:
           - arch: x64
-            runner: macos-13
+            runner: macos-15-intel
             cache-key: intel
             out-dir: ./build/macosx/x86_64/release/crossdesk
             package_script: ./scripts/macosx/pkg_x64.sh