Use secure CRAN mirror

[csgillespie]

A simple one character PR to use the https CRAN mirror instead of the http

[sckott]

thanks!

[sckott]

Actually, @csgillespie we should probably switch to using https://cloud.r-project.org/ - i think that's the global CDN they have and is default for their IDE. Can you make that change?

[csgillespie]

Good spot - List of cran mirrors. Sorry, I didn't think to check.

[csgillespie]

As an aside, a reasonable additional argument to debian_install_r(), would be rprofile with the default value of options(repos=c(\'https://cloud.r-project.org/\')).

The rationale is that some people might want to use the RSPM, but you need to be careful with your Ubuntu version. You might also want to tweak other arguments, e.g. Ncpus in options

Happy to make another PR if you want.

[sckott]

Good idea to have a parameter rprofile - can you send another PR for that?