Scheduler's CronSpec does not work with datetime.timezone offset

[matejscerba]

Taskiq version

0.12.1

Python version

Python 3.13

OS

macOS

What happened?

When serializing and subsequently validating CronSpec with offset as datetime.timezone, the validated instance contains string representation of the offset, which is not valid:

>>> CronSpec.model_validate(CronSpec(offset=datetime.datetime.now().astimezone().tzinfo.utcoffset(None)).model_dump(mode="json"))
CronSpec(minutes='*', hours='*', days='*', months='*', weekdays='*', offset='PT2H')
>>> datetime.datetime.now().astimezone().tzinfo.utcoffset(None)
datetime.timedelta(seconds=7200)

Kicking the tasks uses .model_dump(mode="json"), which is what breaks the timezone-typed value.

Relevant log output

Broker initialization code