renv::dependencies() returns R as a "Package"

[cjyetman]

When a DESCRIPTION file specifies a minimum version of R in Depends, renv::dependencies() returns R as a "Package", though that's not completely correct since there is no R package named "R". I suspect there's some good reason for renv::dependencies() to include the specified minimum version of R in its return value/object, but it would be nice if it was somehow clearly marked as not-really-a-package. I was using renv::dependencies()[['Package']] to feed into e.g. pak::pak(renv::dependencies()[['Package']]), which worked fine until I added a DESCRIPTION file to a non-R-package project that specified a minimum R version.

[kevinushey]

Thanks for the bug report -- I agree we should likely just exclude R in these cases.