package/setools: add comment about Python 3.x dependency
Commit 09b94b1e8f94d1f49f7a2349b4c8cbfecefa73da forgot to add the
usual comment that python3 dependency is due to python-networkx.
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>