update readme and pub description

README.md

 # Bugly-Flutter-Plugin
 
-Flutter工程可以通过集成此插件实现bugly crash捕获、上报的功能。
+Flutter app can use this plugin to monitor exception happened and upload error or crash to bugly server.
 
-使用方式可以参考工程代码和demo示例。
+this plugin is developed base on bugly native crash sdk.
 
-flutter插件是基于native sdk(Android/IOS)的封装，在接入过程如有疑问可以结合原生sdk文档一起参照
+Android Native Sdk Doc： https://bugly.qq.com/docs/user-guide/instruction-manual-android/?v=20181014122344
 
-Android crash 接入文档： https://bugly.qq.com/docs/user-guide/instruction-manual-android/?v=20181014122344
-
-IOS crash 接入文档： https://bugly.qq.com/docs/user-guide/instruction-manual-ios/?v=20181014122344
+iOS Crash Native Sdk Doc： https://bugly.qq.com/docs/user-guide/instruction-manual-ios/?v=20181014122344

pubspec.yaml

 name: bugly_crash
-description: bugly crash plugin
-version: 0.0.2
+description: Flutter app can use this plugin to monitor exception happened and upload error or crash to bugly server.
+version: 0.0.3
 homepage: https://bugly.qq.com
 
 environment: