参考文档：
https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/uniform-message/uniformMessage.send.html

请求参数
{
    "touser": "---", //用户小程序openid 
    "mp_template_msg": {
        "data": {//消息模板数据
            "number9": {
                "value": "12"
            }, 
            "character_string2": {
                "value": "订单签收"
            }, 
            "thing3": {
                "value": "120"
            }, 
            "thing5": {
                "value": "订单"
            }, 
            "first": {
                "value": "积分增加"
            }
        }, 
        "appid": "--",//公众号appid 
        "template_id": "EgWgsQnMBAPUQsRtJ5gDbc9WbGG9BasrEvnsez_671A",//公众号消息模板id
        "miniprogram": {
            "pagepath": "index?foo=bar", 
            "appid": "--"// 小程序appid
        }
    }
}

返回结果如下：
{"errcode":40037,"errmsg":"invalid template_id rid: 62ef6ed3-172a764e-4d2a35bf"}