FCMの対象端末へのプッシュ通知をGAS使って簡単に実現する ref: https://qiita.com/k_keisuke/items/f670d2a3d7f78126f2f5

main.gs

Const = {
  FCMServerKey: "AAAAW1C_znk:APA91bHcG..."
}

function sendNotification(token, value1, value2) {
  var data = {
    "to": token,
    "data":{
      "value1": value1, //hogehoge
      "value2": value2  //mogemoge
    }
  }
  var auth = "key=" + Const.FCMServerKey;
  var headers = {
    'Authorization': auth,
    "contentType" : "application/json",
  };
  var options = {
     "method" : "post",
     "payload" : data,
     "headers" : headers,
     "muteHttpExceptions": true
  };

  var url = "https://fcm.googleapis.com/fcm/send";

  var res = UrlFetchApp.fetch(url, options);
  Logger.log(res);
  return res;
}