Add a `render-readme.yaml` GH action

[jdhoffa]

This package uses a README.Rmd style README. It is common to forget to knit this README, and risk that the README.md falls out of sync.

This is a suggestion to add a GH action to keep track of this.

Relates to RMI-PACTA/r2dii.match#444
(The action can just be copied directly from there, if you are comfortable with an action automatically pushing to your PRs.)

[MonikaFu]

I believe that we used this action for a while but it was causing issues, that is why we removed it (me and Mauro). We can try to re-introduce it though.

[jdhoffa]

That makes sense! It was causing me headaches too, but I managed to get it to work in RMI-PACTA/r2dii.match#444

I leave it up to you, if you think it's something you may want then keep this open, otherwise feel free to close it with no action!

[MonikaFu]

Thanks! Let's try your solution then. Doesn't need to be for this release, though.

[jdhoffa]

Reopening because apparently #554 didn't work.