update readme

app/src/main/java/com/kongzue/dialogxdemo/App.java

@@ -20,6 +20,5 @@ public class App extends BaseApp<App> {
         DialogX.globalStyle = new MaterialStyle();
         DialogX.globalTheme = DialogX.THEME.AUTO;
         DialogX.onlyOnePopTip = false;
-        DialogX.onlyOnePopNotification = false;
     }
 }