beta版 readme

@@ -16,7 +16,8 @@
 [Update log](https://github.com/OpenFlutter/flutter_screenutil/blob/master/CHANGELOG.md)
 
 ## Note
-v3 requires `flutter >= 1.19.0`. Use v2 for current stable version of flutter.
+v3 requires `flutter >= 1.19.0`. 
+v2 for current stable version of flutter.
 
 ## Usage:
 

@@ -4,9 +4,9 @@
 
 [![pub package](https://img.shields.io/pub/v/flutter_screenutil.svg)](https://pub.dartlang.org/packages/flutter_screenutil)
 
-
 **flutter 屏幕适配方案，让你的UI在不同尺寸的屏幕上都能显示合理的布局!**
 
+
 *注意*：此插件仍处于开发阶段，某些API可能尚未推出。
 
 [README of English](https://github.com/OpenFlutter/flutter_ScreenUtil/blob/master/README.md)
@@ -19,6 +19,10 @@
 
 [更新日志](https://github.com/OpenFlutter/flutter_screenutil/blob/master/CHANGELOG.md)
 
+## Note
+v3 requer `flutter> = 1.19.0`.
+v2 é usado para a versão atual de flutter estável.
+
 ## 使用方法:
 
 ### 安装依赖：

@@ -15,6 +15,7 @@
 
 [Histórico de atualizações](https://github.com/OpenFlutter/flutter_screenutil/blob/master/CHANGELOG.md)
 
+
 ## Como usar:
 
 ### Adicionando a dependência：