Wrong hourly validation

[robertHowlett]

Steps to reproduce

import cron_validator
cron_validator.CronScheduler("*/60 * * * *").time_for_execution()

Expected behaviour: we get True on minute zero, otherwise false

Actual behaviour:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "...\Python312\site-packages\cron_validator\scheduler.py", line 10, in __init__
    self.next_execution_time = next(self.gen)
                               ^^^^^^^^^^^^^^
  File "...\Python312\site-packages\cron_validator\validator.py", line 76, in get_execution_time
    if cls.match_datetime(expression, dt, version):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "...\Python312\site-packages\cron_validator\validator.py", line 59, in match_datetime
    elements = cls.parse(expression, version)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "...\Python312\site-packages\cron_validator\validator.py", line 23, in parse
    raise ValueError(f"Invalid expression part {i}")
ValueError: Invalid expression part 0

Crontab.guru says that this expression is fine