license: update years and authors
license: update years and authors

This obviously hasn't been updated since the site started.
There's not much point in trying to list all of the authors,
so I'll just say "and others". Anybody who really wants to
know can use `git log`.

(I doubt anybody cares that much at all, but since we're now
linking the license file from the "about" page, it may get
more attention).

git/git-scm.com,mosoft521/gitscm-next,git/git-scm.com,git/git-scm.com,Mokolea/git-scm.com,mosoft521/gitscm-next,mosoft521/gitscm-next,Mokolea/git-scm.com,Mokolea/git-scm.com,Mokolea/git-scm.com,mosoft521/gitscm-next,git/git-scm.com