bump to 2.4.2

CHANGELOG.md

+## 2.4.2
+* Fix #317
+
 ## 2.4.1
 * 修复Android 11无法分享图片的问题
 

pubspec.yaml

 name: fluwx
 description: The capability of implementing WeChat SDKs in Flutter. With Fluwx, developers can use WeChatSDK easily, such as sharing, payment, lanuch mini program and etc.
-version: 2.4.1
+version: 2.4.2
 homepage: https://github.com/JarvanMo/fluwx
 
 environment: