macchanger: bump to version 1.6.0

Also switch the homepage, it's not a proper one but at least it's no
longer a 404.
The license is now GPLv2+ but there's no COPYING file.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>