Subject: adding r-crew package to the guix packages

From: Javier Vaquero Martínez <[email-masked]>
Date: Tue, 11 Mar 2025 20:16:40 +0100

Dear maintainers,

The package r-crew is needed by r-targets in order to use parallel 
processing. I think it would be nice that it was available in guix 
channel because r-targets is in guix channel. Moreover, the guix-cran 
version does not install, it fails when trying to install r-nanonext. I 
have not been able to make it work either.

Thank you in advance,

Javier.