R 4.0.0 for bullseye and buster

[Johannes Ranke <johannes.ranke@jrwb.de>]

Dear all,

I set up new repositories on CRAN for R 4.0.0 and the recommended packages. As 
the transition will probably still take a while, I also created a repo for 
bullseye. If you would like to use R 4.0.0 from these repos, you first need to 
remove r-base-core which will remove all the Debian packaged extensions, then 
install r-base and update your locally installed packages as described here

  https://cran.r-project.org/bin/linux/debian/#debian-bullseye-testing

I am not currently supporting R 4.0.0 on stretch, as I am not using it. Let me 
know if you need it.

Kind regards,

Johannes

P.S.: I forgot to update the repo line for buster at first, the fix is on its 
way. It has to be buster-cran40 of course.