chore!: removing the deprecated api in favor of latest

router.mountSubRouter("/eventbus", subRouter);
To 
router.route("/eventbus/*").subRouter(subRouter);

Author: sanjuthomas

web-examples/src/main/java/io/vertx/example/web/realtime/Server.java

@@ -43,7 +43,7 @@ public void start() throws Exception {
       event.complete(true);
 
     });
-    router.mountSubRouter("/eventbus", subRouter);
+    router.route("/eventbus/*").subRouter(subRouter);
 
 
     // Serve the static resources