Use timezone-aware datetimes -- ruff check --select=DTZ

[cclauss]

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

% ruff check --select=DTZ --statistics

17	DTZ001	The use of `datetime.datetime()` without `tzinfo` argument is not allowed
 5	DTZ005	The use of `datetime.datetime.now()` without `tz` argument is not allowed
 4	DTZ003	The use of `datetime.datetime.utcnow()` is not allowed, use `datetime.datetime.now(tz=)` instead

% ruff rule DTZ001

call-datetime-without-tzinfo (DTZ001)

Derived from the flake8-datetimez linter.

What it does

Checks for datetime instantiations that lack a tzinfo argument.

Why is this bad?

datetime objects are "naive" by default, in that they do not include
timezone information. "Naive" objects are easy to understand, but ignore
some aspects of reality, which can lead to subtle bugs. Timezone-aware
datetime objects are preferred, as they represent a specific moment in
time, unlike "naive" objects.

By providing a tzinfo value, a datetime can be made timezone-aware.

Example

import datetime

datetime.datetime(2000, 1, 1, 0, 0, 0)

Use instead:

import datetime

datetime.datetime(2000, 1, 1, 0, 0, 0, tzinfo=datetime.timezone.utc)

Or, for Python 3.11 and later:

import datetime

datetime.datetime(2000, 1, 1, 0, 0, 0, tzinfo=datetime.UTC)

[jcjones]

Woohoo!