Moved to Java 21

Author: boyninja1555

.github/workflows/release.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: "temurin"
-          java-version: "17"
+          java-version: "21"
 
       - name: Build fat JAR
         run: mvn clean package