[feature] Format the code and improve Mini Program authorization to o… (#473)

* [feature] Format the code and improve Mini Program authorization to obtain openid（miniprogram/auth/auth.go Code2Session）

* [feature] CheckEncryptedData (https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/user-info/auth.checkEncryptedData.html)

* upgrade json error

* upgrade json error

Co-authored-by: houseme <houseme@outlook.com>

pay/pay.go

@@ -8,12 +8,12 @@ import (
 	"github.com/silenceper/wechat/v2/pay/transfer"
 )
 
-//Pay 微信支付相关API
+// Pay 微信支付相关API
 type Pay struct {
 	cfg *config.Config
 }
 
-//NewPay 实例化微信支付相关API
+// NewPay 实例化微信支付相关API
 func NewPay(cfg *config.Config) *Pay {
 	return &Pay{cfg}
 }