devel/R-cran-git2r: add ports

Interface to the 'libgit2' library, which is a pure C implementation of the
'Git' core methods. Provides access to 'Git' repositories to extract data and
running some basic 'Git' commands.

WWW: https://CRAN.R-project.org/package=git2r

PR:		243627
Submitted by:	jpbeconne@free.fr