Bump to version 3.1, as somehow a v3 has alreday been pushed to Pypi.
Bump to version 3.1, as somehow a v3 has alreday been pushed to Pypi.

Signed-off-by: Philippe Ombredanne <ca95c4a6a4931f366cbdaf5878c5016609417d37@nexb.com>
pombredanne/boolean.py,bastikr/boolean.py