文档地址：https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/ministore/minishopopencomponent2/API/public/upload_img.html

提交参数："{"resp_type":1,"upload_type":1,"img_url":"https:\/\/img.alicdn.com\/imgextra\/i2\/2487257158\/O1CN0155fNMC22kPiCCsrZq_!!2487257158.jpg"}"

返回错误信息：
["errcode"] => int(1070001)
  ["errmsg"] => string(51) "文件/图片为空 rid: 6258e3cc-562c7019-17034d8f"