Update dependencies

Do not update Hubot to v4 or upper.
ref: slackapi/hubot-slack#653
Do not update CoffeeScript to v2 because unknown error occurred.
Do not update node-fetch to v3 because it is ES Module.

```shell
$ ncu --reject coffeescript,node-fetch -u
$ (edit line of "hubot" in package.json)
$ npm install
```