Since version 6.0.0, the package supports only Python 3, and will
lead to syntax errors when in use with Python 2.
In addition, the dependency of python-six is no longer needed.
The reursive reverse dependencies were updated accordingly.
Signed-off-by: Asaf Kahlon <asafka7@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>