Copyright for libextractor source package in Bionic

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: Libextractor
Upstream-Contact: Christian Grothoff 
Source: https://www.gnu.org/software/libextractor/
License: GPL-3+

Files: *
Copyright:
 (C) 2002-2017 Christian Grothoff 
 (C) 2002-2005 Vidyut Samanta 
License: GPL-3+

Files: debian/*
Copyright:
 (C) 2012-2017 Bertrand Marc 
 (C) 2004-2012 Daniel Baumann 
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.
 .
 The complete text of the GNU General Public License
 can be found in /usr/share/common-licenses/GPL-3 file.