`recommonmark` is deprecated

[sobolevn]

https://github.com/readthedocs/recommonmark#recommonmark

We should switch to myst: https://github.com/executablebooks/MyST-Parser

[radiantly]

Hi, could I take this up?

[sobolevn]

Sure, @radiantly! Thanks! Please, note that Hactoberst hasn't started yet. You need to wait for several days 🙂
Otherwise, this won't be counted by their rules.