Copyright for zssh source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: zssh
Source: http://zssh.sourceforge.net/
Comment: lrzsz source files are removed. See individual lrzsz package.

Files: *
Copyright: 2000-2001 Matthieu Lucotte 
License: GPL-2+

Files: debian/*
Copyright:
 2003, Daniel Bungert 
 2005, Andrew Pollock 
 2005, Matej Vela 
 2005-2007, Bart Martens 
 2007, Ben Wong 
 2017-2018, Boyuan Yang 
License: GPL-2+

License: GPL-2+
 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; either version 2 of the License, or
 (at your option) any later version.
 .
 This package 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 program.  If not, see .
 .
 On Debian systems, the complete text of the GNU General Public License
 version 2 can be found in `/usr/share/common-licenses/GPL-2'.