我的 Discord 机器人无法与 Heroku 正常工作，有人知道原因吗？我将给出我在尝试部署机器人时收到的错误消息，如果你们需要有关我的程序中的文件的信息，只需 lmk！谢谢
2021-08-31T03:57:41.760749+00:00 heroku[worker.1]: Starting process with command `node index.js`
2021-08-31T03:57:42.368542+00:00 heroku[worker.1]: State changed from starting to up
2021-08-31T03:57:44.139912+00:00 heroku[worker.1]: Process exited with status 1
2021-08-31T03:57:44.213728+00:00 heroku[worker.1]: State changed from up to crashed
2021-08-31T03:57:44.057396+00:00 app[worker.1]: /app/node_modules/discord.js/src/rest/APIRequest.js:33
2021-08-31T03:57:44.057418+00:00 app[worker.1]: agent ??= new https.Agent({ ...this.client.options.http.agent, keepAlive: true });
2021-08-31T03:57:44.057419+00:00 app[worker.1]: ^^^
2021-08-31T03:57:44.057419+00:00 app[worker.1]:
2021-08-31T03:57:44.057419+00:00 app[worker.1]: SyntaxError: Unexpected token '??='
2021-08-31T03:57:44.057420+00:00 app[worker.1]: at wrapSafe (internal/modules/cjs/loader.js:988:16)
2021-08-31T03:57:44.057420+00:00 app[worker.1]: at Module._compile (internal/modules/cjs/loader.js:1036:27)
2021-08-31T03:57:44.057420+00:00 app[worker.1]: at Object.Module._extensions..js (internal/modules/cjs/loader.js:1101:10)
2021-08-31T03:57:44.057420+00:00 app[worker.1]: at Module.load …