Incorrect parsing "24" hour

[vakhet]

Hello!

Stumbled on this strange behavior, consider myself as a bug, what do you think?

Python 3.8.1 (v3.8.1:1b293b6006, Dec 18 2019, 14:08:53)
[Clang 6.0 (clang-600.0.57)] on darwin
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>>> import ciso8601
>>> ciso8601.parse_datetime("2020-02-28T23:00:00Z")
datetime.datetime(2020, 2, 28, 23, 0, tzinfo=datetime.timezone.utc)
>>> ciso8601.parse_datetime("2020-02-28T24:00:00Z")
datetime.datetime(2020, 2, 29, 0, 0, tzinfo=datetime.timezone.utc)
>>> ciso8601.parse_datetime("2020-02-28T25:00:00Z")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: hour must be in 0..23

It is not only passes "24" hour, but also returns different date. Logic is obvious (next day, 00 hour), but behavior is incorrect IMHO
"2020-02-28T24:00:00Z" != datetime.datetime(2020, 2, 29, 0, 0, tzinfo=datetime.timezone.utc)

Also, 24 is not in range 00..23

[movermeyer]

This actually was a valid ISO 8601 datetime.

Prior to ISO 8601-1:2019, 24:00 was a valid time in ISO 8601.

However, as of ISO 8601-1:2019, it has been explicitly disallowed.

We haven't figured out how exactly to handle this evolution of the specification within ciso8601's interface.

Tracking this in #100