Feat: client-upload file in oss

pkg/serializer/upload.go

@@ -18,8 +18,10 @@ type UploadPolicy struct {
 
 // UploadCredential 返回给客户端的上传凭证
 type UploadCredential struct {
-	Token  string `json:"token"`
-	Policy string `json:"policy"`
+	Token     string `json:"token"`
+	Policy    string `json:"policy"`
+	Path      string `json:"path"`
+	AccessKey string `json:"ak"`
 }
 
 // UploadSession 上传会话