Support `datetime.timedelta` as a valid wait unit type (#342)

* Support `datetime.timedelta` as a valid wait unit type

Signed-off-by: Noam Bloom <nbloom5@bloomberg.net>

* Add datetime.timedelta support tests

Signed-off-by: Noam Bloom <nbloom5@bloomberg.net>

Co-authored-by: Noam Bloom <nbloom5@bloomberg.net>
Co-authored-by: Julien Danjou <julien@danjou.info>
3 files changed