gnu-efi pkg points to the outdated sourceforge repo

[Nir Lichtman <nir@lichtman.org>]

Hello,

The gnu-efi package has decided ~1 year ago to move
the repository from Sourceforge to Github and hence
the repo on Sourceforge is no longer maintained.
The Debian package still refers to the Sourceforge repo.

The updated Github repo is linked on the landing page
of the project on Sourceforge.

Thanks,
Nir