Copyright for ubuntu-unity-meta source package in Mantic

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/

Files: *
Copyright: 2018 Ubuntu Unity Developers 
License: GPL-2+
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; version 2 dated June, 1991, or (at
 your option) any later version.
 .
 On Debian systems, the complete text of version 2 of the GNU General
 Public License can be found in '/usr/share/common-licenses/GPL-2'.