docs(outdated): outdated documentation in official site

[Kristinita]

1. Summary

Stylint documentation in https://simenb.github.io/stylint/ outdated. It would be nice, if you:

1. Update documentation in https://simenb.github.io/stylint/ page.

or

2. Add in beginning of https://simenb.github.io/stylint/ message as This documentation is outdated. Please, see the relevant version [**here**](https://github.com/SimenB/stylint/blob/master/README.md)

2. Argumentation

Stylint users (I include) may think, that actual documentation in https://simenb.github.io/stylint/ page. Users can apply obsolete options, values and so on.

Thanks.

[the-j0k3r]

see #375