[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>

officialaccount/message/image.go

@@ -1,6 +1,6 @@
 package message
 
-//Image 图片消息
+// Image 图片消息
 type Image struct {
 	CommonToken
 
@@ -9,7 +9,7 @@ type Image struct {
 	} `xml:"Image"`
 }
 
-//NewImage 回复图片消息
+// NewImage 回复图片消息
 func NewImage(mediaID string) *Image {
 	image := new(Image)
 	image.Image.MediaID = mediaID