Heroku 上的 Discord 机器人抛出错误:agent ??= new https.Agent

This is related to my first question. I updated all of my codes. In my bot.js is:

require('dotenv').config();

let ver = process.env.DISCORD_BOT;

client.once('ready', async () => {
  if (ver === 'production') {
    client.user.setActivity(`in code land`, { type: 'PLAYING' });
  } else {
    client.user.setActivity(`over ${client.guilds.cache.size} server(s)`, {
      type: 'WATCHING',
      status: 'IDLE',
    });
  }
  console.log(`Logged in as ${client.user.tag}!`);
  console.log(`the prefix is ` + prefix);
});

过程文件:

worker: node bot.js

package.json:

 "scripts": {
    "start": "node .",
    "test": "echo "Error: no test specified" && exit 1",
    "production": "NODE_ENV=production&&npm start",
    "development": "set NODE_ENV=development&&npm start"
  }

.env:

DISCORD_BOT= TOKEN

当我检查 Heroku 应用程序日志时，抛出的错误如下:

  "engines": {
    "node": "16.6"
  }

  "engines": {
    "node": "16.x"
  }