Use macOS 15 directly, later can be returned to macos-latest

Author: introfog

.github/workflows/maven.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest] 
+        os: [ubuntu-latest, macos-15, windows-latest] 
         java-version: [17]
 
     steps: