bump to 4.6.0

CHANGELOG.md

+# 4.6.0
+* Android SDK => 6.8.30
+* 分享新增基础字段:thumbData
+* 分享新增基础字段:thumbDataHash
+
 # 4.5.6
 * Merge #639
 

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: 4.5.6
+version: 4.6.0
 homepage: https://github.com/OpenFlutter/fluwx
 
 environment: