Fix unclosed okhttp response (#532)

(cherry picked from commit 04e971a7caf401bb4c23b87ccdc1e1e779931e3d)
Signed-off-by: CodeInDreams <hui068323@gmail.com>

src/main/java/io/milvus/connection/ClusterListener.java

@@ -34,8 +34,7 @@ public class ClusterListener implements Listener {
                 serverSetting.getServerAddress().getHealthPort());
 
         boolean isRunning = false;
-        try {
-            Response response = get(url);
+        try (Response response = get(url)) {
             isRunning = checkResponse(response);
             if (isRunning) {
                 logger.debug("Host [{}] heartbeat Success of Milvus Cluster Listener.",