Copyright for xxkb source package in Focal

This package was debianized by Artem Chuprina 

It was downloaded from http://xxkb.sourceforge.net

Copyright (c) 1999-2009, by Ivan Pascal 

Artistic license. On Debian systems, full text of Artistic
license is alailable in /usr/share/common-licenses/Artistic.

Debian packaging is (C) 2000-2009 Artem Chuprina 
and is licensed under the Artistic, see /usr/share/common-licenses/Artistic.