Fixed
- `AttributeError` when passing `pandas.Timestamp`s with different timezones (*of which one was UTC*) to `DatapointsAPI.retrieve_dataframe_in_tz`.
- A `ValueError` is no longer raised when passing `pandas.Timestamp`s in the same timezone, but with different underlying implementations (e.g. `datetime.timezone.utc` / `pytz.UTC` / `ZoneInfo("UTC")`) to `DatapointsAPI.retrieve_dataframe_in_tz`.