https://developers.line.biz/console/
create 一個 provider, messaging api channel
取得 Channel secret 與 messaging api 的 Channel access token
設定 關閉自動回應、webhook 啟用 (hook url 需要 https 連入)
https://beta.openai.com/account/api-keys
申請 openai API key
LINE_CHANNEL_ACCESS_TOKEN=
LINE_CHANNEL_SECRET=
OPENAI_API_KEY=