bump to 3.12.1

CHANGELOG.md

+# 3.12.1
+* 升级AGP
+* Fix #512
+
 # 3.12.0
 * 授权登录支持关闭自动授权
 * 分享支持添加签名，防止篡改

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: 3.12.0
+version: 3.12.1
 homepage: https://github.com/JarvanMo/fluwx
 
 environment: