https://genesis-aka.net/language/japanese/2021/01/28/google-cloud-functions%e3%81%8cruby%e3%81%ae%e3%82%b5%e3%83%9d%e3%83%bc%e3%83%88%e3%82%92%e7%99%ba%e8%a1%a8-%e3%83%ad%e3%83%bc%e3%82%ab%e3%83%ab%e7%92%b0%e5%a2%83%e3%81%a7%e3%81%ae%e9%96%8b%e7%99%ba/