Add license/copyright; copied from CharacterTest.h

src/autotests/CharacterTest.cpp

+/*
+    SPDX-FileCopyrightText: 2019 Tomaz Canabrava <tomaz.canabrava@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
 #include "CharacterTest.h"
 #include "Character.h"