Switch MacOS to 15

As per  actions/runner-images#13046
.

Author: akurtakov

.github/workflows/maven.yml

@@ -34,7 +34,7 @@ jobs:
         config: 
           - { name: Linux, os: ubuntu-latest, native: gtk.linux.x86_64 }
           - { name: Windows, os: windows-latest, native: win32.win32.x86_64 }
-          - { name: MacOS x86, os: macos-13, native: cocoa.macosx.x86_64 }
+          - { name: MacOS x86, os: macos-15-intel, native: cocoa.macosx.x86_64 }
           - { name: MacOS ARM, os: macos-latest, native: cocoa.macosx.aarch64 }
     name: Verify ${{ matrix.config.name }} with Java-${{ matrix.java }}
     runs-on: ${{ matrix.config.os }}