fix(ci): add Java 21 setup to workflow

Author: Jose Angel

.github/workflows/java.yml

@@ -13,11 +13,14 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v4
 
-    - name: Install ANTLR4 and Maven
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y maven
-        make dev
+    - name: Set up Java 21
+      uses: actions/setup-java@v4
+      with:
+        distribution: 'temurin'
+        java-version: '21'
+
+    - name: Install ANTLR4
+      run: make dev
 
     - name: Import GPG key
       uses: crazy-max/ghaction-import-gpg@v6