http请求方式：POST https://api.weixin.qq.com/product/order/upload_refund_certificate?access_token=xxxxxxxxx
{ "order_id": 1768715750567651, // 售后单号 "refund_certificates": ["media_id1", "media_id2"], // 退款凭证 "desc": "", // 描述 }
{ "errcode":0 // 返回码 }
