Add unit tests for me.zhyd.oauth.utils.GlobalAuthUtil

These tests were written using Diffblue Cover.

Merge pull request !4 from skqing/master

调整部分代码

参考：https://github.com/giantray/stackoverflow-java-top-qa/blob/master/contents/comparing-java-enum-members-or-equals.md

1. 字符串形式的 utf-8 会抛异常
2. Charset 的性能要好

1.remind_in：该参数即将废弃，开发者请使用expires_in
2.uid作为openid，否则openid为空，理论上uid也是可以作为openid的

🏗 架构调整，简化代码

1.抖音的client_id换成client_key了
2.抖音的地址后面必须加上/否则报错

# Conflicts:
#	src/main/java/me/zhyd/oauth/request/AuthAlipayRequest.java
#	src/main/java/me/zhyd/oauth/request/AuthQqRequest.java

Merge pull request !2 from skqing/master