RFE: use `zoneinfo` instead of `pytz`

[kloczek]

Switch to standard zoneinfo module. Below may help https://github.com/pydantic/pydantic-core/commit/fd262933

[tkloczko@pers-jacek arrow-1.3.0]$ grep -r pytz
CHANGELOG.rst:- [FIX] Fixed a bug that occurred when ``arrow.Arrow()`` was instantiated with a ``pytz`` tzinfo object.
CHANGELOG.rst:- [FIX] Fix pytz conversion error (Kudo)
README.rst:- Too many modules: datetime, time, calendar, dateutil, pytz and more
README.rst:- Support for ``dateutil``, ``pytz``, and ``ZoneInfo`` tzinfo objects
arrow/arrow.py:        # detect that tzinfo is a pytz object (issue #626)
requirements/requirements-tests.txt:pytz==2021.1
tests/test_arrow.py:import pytz
tests/test_arrow.py:    def test_init_pytz_timezone(self):
tests/test_arrow.py:            2013, 2, 2, 12, 30, 45, 999999, tzinfo=pytz.timezone("Europe/Paris")
tests/test_formatter.py:import pytz
tests/test_formatter.py:        dt = datetime(1986, 2, 14, tzinfo=pytz.timezone("UTC")).replace(
tests/utils.py:import pytz
tests/utils.py:    pytz_zones = set(pytz.all_timezones)
tests/utils.py:    return dateutil_zones.union(pytz_zones)
pyproject.toml:    "pytz==2021.1",

[jadchaar]

Hi @kloczek thanks for raising the issue. Contributions are welcome to add this functionality to Arrow :)