d/a/copyright: Add missing copyright information

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>

debian/apertis/copyright.whitelist

+# LGPL-3+ licensed files only used for testing purposes, not distributed
+gio/tests/memory-monitor-portal.py.in
+gio/tests/memory-monitor-dbus.py.in

debian/apertis/copyright.yml

+.*:
+  license: LGPL-2.1-or-later