Add CI step to render HTML

[jbteves]

We should add a CI step to render HTML for convenience.

[notZaki]

I think netlify has the ability to create a webpage preview of each PR.
Otherwise, there's htmlpreview, which would look like this for the current PR.

[jbteves]

htmlpreview looks perfect to me and is a lightweight solution. We could just add it to the README. WDYT @tsalo ?

[notZaki]

One potential issue with htmlpreview is that some hyperlinks don't resolve correctly. For example, urls ending with #anchor fail in the current preview.

An alternative is to just write the draft in markdown instead of html. Github will render the markdown. It can then be converted to plain html using pandoc.

[emdupre]

I use netlify regularly, and can vouch that it's very dev-friendly :)

But I like your suggestion to convert at the end, @notZaki !

One idea : store markdown in github on main branch, use a github action to convert these to plain html with pandoc and add to a gh-pages branch, which we can render. I do something similar in spirit here: https://github.com/emdupre/nha2020-nilearn/blob/1c9add5f3049a51f34b0284fe0e870b21579f8c9/.github/workflows/book.yml#L32-L42