Copyright for xfpanel-switch source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: Xfce Panel Switch
Upstream-Contact: Sean Davis 
Source: https://launchpad.net/xfpanel-switch

Files: *
Copyright: 2013, Alistair Buxton 
           2015-2018, Sean Davis 
License: GPL-3+

Files: debian/*
Copyright: 2015-2018, Sean Davis 
           2015, Unit 193 
License: GPL-3+

License: GPL-3+
 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; either version 3 of the License, or (at your option) any later
 version.
 .
 This program is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 .
 You should have received a copy of the GNU General Public License along with
 this package; if not, write to the Free Software Foundation, Inc., 51 Franklin
 St, Fifth Floor, Boston, MA  02110-1301 USA
 .
 On Debian systems, the full text of the GNU General Public License version 3
 can be found in the file `/usr/share/common-licenses/GPL-3'.