发送图文消息(mpnews)
https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=
{"touser":"","msgtype":"mpnews","mpnews":{"media_id":"qTGX-2l64YYDNi03o-_vtlX828rndnpj1byzwHYOZxIbdFZW4YqY7SPN9DC-c7T-"}}
media_id取自于获取成功发布列表https://api.weixin.qq.com/cgi-bin/freepublish/batchget?access_token= 的返回参数 article_id
invalid media_id rid: 66e15cca-0a65c6d7-7b6ef3fe
article_id 应使用 mpnewsarticle 消息类型下发：https://developers.weixin.qq.com/doc/offiaccount/Message_Management/Service_Center_messages.html#%E5%AE%A2%E6%9C%8D%E6%8E%A5%E5%8F%A3-%E5%8F%91%E6%B6%88%E6%81%AF