Fix Java version

Author: swa-ds

.github/workflows/maven-build.yml

@@ -22,10 +22,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - name: Set up JDK 12
+      - name: Set up JDK 21
         uses: actions/setup-java@v3
         with:
-          java-version: '12'
+          java-version: '21'
           distribution: 'temurin'
           cache: maven
       - name: Build with Maven