adding renv as a detectable R version provider #321

Description

Now that arf has this wonderful new ability to detect when a project uses a specific R version and launch the REPL with that R version, I was wondering whether it would be possible to add renv as an additional provider for this feature? As far as I can see, it's not currently covered by the current implementation.

Motivation

I still have some older projects that use renv and it would be nice if these could take advantage of the arf feature too. renv was probably the most popular tool for R project management for a long time, so I'm sure I'm not alone here. I think the renv.lock file would be a pretty reliable target for this, it seems to just be JSON.

Alternatives considered

No response

Additional context

No response