Supports str hash_id in is_valid() as in __init__()

[george-kuanli-peng]

Before:

>>> croniter.is_valid('H 0 * * *', hash_id='abc')
Traceback (most recent call last):
...
TypeError: a bytes-like object is required, not 'str'

After:

>>> croniter.is_valid('H 0 * * *', hash_id='abc')
True

[kiorky]

I'll add some bits before release.

[kiorky]

Thx for the contribution !

[kiorky]

released: https://pypi.org/project/croniter/2.0.5/