Bump qtmacextras version to 5.2.0

Change-Id: I6e1f329b2d4bcf6b54a9db078c5f7064224e8480
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Reviewed-by: Jani Heikkinen <jani.heikkinen@digia.com>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>