Fix deprecation warnings for `datetime.utcnow()` by tomasr8 · Pull Request #1119

Fix deprecation warnings for `datetime.utcnow()` by tomasr8 · Pull Request #1119 · python-babel/babel

This shows up when running the tests on 3.12:

~dev/babel/tests/test_dates.py:757: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to rep
resent datetimes in UTC: datetime.datetime.now(datetime.UTC).                                                                                                                                 
    assert dates.format_datetime(datetime.utcnow(), locale="ja_JP@mod")

I think there's no harm in using plain datetime.now() for these tests.