Wrong weekday range

[agileshaw]

The weekday range should be 0-6 as specified in Cron. However, croniter is accepting 7 as a valid weekday value.

Current:

>>> from croniter import croniter
>>> croniter.is_valid("* * * * 7")
True
>>>

Expecting:

>>> from croniter import croniter
>>> croniter.is_valid("* * * * 7")
False
>>>

The line causing the error seems to be:

croniter/src/croniter/croniter.py

Line 140 in 4d6bb97

(0, 7),