pre-commit: Add ruff rules for unsafe naive datetimes

[cclauss]

Fixes: #1059

Lint rules to ban the usage of unsafe naive datetimes.

• https://docs.astral.sh/ruff/rules/#flake8-datetimez-dtz

% ruff check --select=DTZ --statistics

7	DTZ001	call-datetime-without-tzinfo
7	DTZ005	call-datetime-now-without-tzinfo
5	DTZ003	call-datetime-utcnow
Found 19 errors.

Related to:

• DatabaseScheduler.schedule().current_time is a naive datetime #1059

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 87.90%. Comparing base (6594458) to head (8a858f7).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
django_celery_beat/schedulers.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1060   +/-   ##
=======================================
  Coverage   87.90%   87.90%           
=======================================
  Files          32       32           
  Lines        1025     1025           
  Branches       84       84           
=======================================
  Hits          901      901           
  Misses        106      106           
  Partials       18       18           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[auvipy]

I think this change and the one above demands unit tests for verification. @alirafiei75 what do you think?

[alirafiei75]

I do not think that is critical because both of the changes do not make any logical difference and there are already unit tests on the function. but it wouldn't hurt.