Teach Automake that COPYING* files are gone from sources

The COPYING* files are not in the source distribution anymore.
Furthermore, LICENSE.txt and license-change-2020.txt files were newly
added.  This patch updates Makefile.am accordingly.

	* Makefile.am: Teach Automake that COPYING* files are gone and
	that LICENSE.txt and license-change-2020.txt were added.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
1 file changed