dejagnu: Fix LICENSE

The contents of the COPYING file included in the current source code
package match those of GPL-3.0-only license, which seems to have been
the case since 2008 commit
http://git.savannah.gnu.org/gitweb/?p=dejagnu.git;a=commitdiff;h=9bebe7b9bfb9b02e5e4d86ad74e8ce3eb32a36b9;hp=50fbdd118dba066e201c73a8b0155381cd65a32d


("* COPYING: Update to GPL version 3.")

(From OE-Core rev: 26b71cfb7815a096c5962629801cc3bc85147284)

(From OE-Core rev: cdedb408247e48f59c948e8c57918b88baf304b4)

Signed-off-by: Niko Mauno <niko.mauno@vaisala.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/recipes-devtools/dejagnu/dejagnu_1.6.3.bb

@@ -2,7 +2,7 @@ SUMMARY = "GNU unit testing framework, written in Expect and Tcl"
 DESCRIPTION = "DejaGnu is a framework for testing other programs. Its purpose \
 is to provide a single front end for all tests."
 HOMEPAGE = "https://www.gnu.org/software/dejagnu/"
-LICENSE = "GPL-2.0-only"
+LICENSE = "GPL-3.0-only"
 LIC_FILES_CHKSUM = "file://COPYING;md5=d32239bcb673463ab874e80d47fae504"
 SECTION = "devel"