It might be used by the Matroska muxer. This is also the reason why the
FATE-tests for muxing WavPack into Matroska needed to be updated: They
now write the correct version 4.07 and not 4.03 as before.
Reviewed-by: David Bryant <david@wavpack.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>