Copyright for squid-deb-proxy source package in Xenial

Format-Specification: http://svn.debian.org/wsvn/dep/web/deps/dep5.mdwn?rev=59

Files: *
Copyright: (c) 2010 Canonical
License: GPL-3

License: GPL-3
 This package 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 3.
 .
 On Debian systems, the complete text of the GNU General
 Public License can be found in `/usr/share/common-licenses/GPL-3'.