bump to 5.5.2

CHANGELOG.md

+# 5.5.2
+* Fix [#703](https://github.com/OpenFlutter/fluwx/issues/703)
+
 # 5.5.1
 * 鸿蒙端bug修复，详见[PR](https://github.com/OpenFlutter/fluwx/pull/700)
 

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: 5.5.1
+version: 5.5.2
 homepage: https://github.com/OpenFlutter/fluwx
 
 environment: