Add java21 build

Author: dizzzz

.github/workflows/ci-test.yml

@@ -39,14 +39,15 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
+        jvm: ['17', '21']
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
       - name: Set up JDK
         uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: ${{ env.DEV_JDK }}
+          java-version: ${{ matrix.jvm }}
           cache: 'maven'
       - name: Install Maven Daemon
         id: install-mvnd