Attempt to run with java 21

Author: graduta

.github/workflows/maven-multi-os.yml

@@ -14,11 +14,11 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v5
-      - name: Set up JDK 16
+      - name: Set up JDK 21
         uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
-          java-version: '16'
+          java-version: '21'
       - name: Compile with Maven
         run: mvn clean compile
       - name: Validate Maven Project