bump to 5.3.0

CHANGELOG.md

+# 5.3.0
+* 升级kotlin、gradle相关
+* 更新progurad规则(#672)
+
 # 5.2.7
 * 鸿蒙sdk升级到1.0.3
 * 鸿蒙支持分享至小程序

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: 5.2.7
+version: 5.3.0
 homepage: https://github.com/OpenFlutter/fluwx
 
 environment: