Copyright for spline source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: aspline
Upstream-Contact: David Frey
Source: http://homepage.hispeed.ch/david.frey/

Files: *
Copyright: 1996-2010 David Frey 
License: GPL-2+

Files: debian/*
Copyright: 1996-2010, David Frey 
  2009-2016, Stuart Prescott 
License: GPL-2+

License: GPL-2+
 On Debian systems, the complete text of the GNU General Public License,
 can be found in /usr/share/common-licenses/GPL-2.