update gh action build

Signed-off-by: Lukas Jungmann <[email protected]>

.github/workflows/maven.yml

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2021, 2022 Contributors to the Eclipse Foundation
+# Copyright (c) 2021, 2024 Contributors to the Eclipse Foundation
 #
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License v. 2.0 which is available at
@@ -29,17 +29,18 @@ jobs:
 
     strategy:
       matrix:
-        java_version: [ 11, 17 ]
+        java_version: [ 11, 17, 21 ]
 
     steps:
       - name: Checkout for build
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Set up JDK
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           distribution: 'zulu'
           java-version: ${{ matrix.java_version }}
+          cache: 'maven'
       - name: Verify
         run: mvn -B -V -U -C -Pstaging,oss-release,build-only clean verify org.glassfish.copyright:glassfish-copyright-maven-plugin:check -Dgpg.skip=true