use -no-install-recommends flag
remove hadleyverse and ropensci from rocker, since they now live in separate repos in rocker-org
Merge remote-tracking branch 'origin/master' into sandbox
no need for temp file to gather rstudio version

this (manually) applies #43 which @pshevtsov had kindly posted and (accidentally ?) withdrawn
moved description of r-devel-san from 'use cases' to 'main'

it has no separate repo, case could be made either way
Merge pull request #44 from rocker-org/sandbox

Sandbox