[arch-dev-public] GPL v3

[Dan McGee]

Since some software we are going to package soon will be released
under GPL v3 instead of GPL v2 or later, should we add this license as
a separate one named "GPLv3" in the licenses package and begin using
this in the license field? This seems like the easiest solution to me,
rather than go back and change every occurrence of GPL to GPLv2.

Thoughts? This isn't a very extreme change, but something that we need
to consider and I didn't want to make the change without a bit of
feedback first.

-Dan