- Update to 2.2.1
## Enhancements
* Added pyarrow pip extra so users can install pandas and pyarrow
with pip with pip install pandas[pyarrow] (#54466)
## Fixed regressions
* Fixed memory leak in `read_csv` (#57039)
* Fixed performance regression in `Series.combine_first` (#55845)
* Fixed regression causing overflow for near-minimum timestamps
(#57150)
* Fixed regression in `concat` changing long-standing behavior
that always sorted the non-concatenation axis when the axis was
a `DatetimeIndex` (#57006)
* Fixed regression in `merge_ordered` raising TypeError for
fill_method="ffill" and how="left" (#57010)
* Fixed regression in `pandas.testing.assert_series_equal`
defaulting to check_exact=True when checking the `Index`
(#57067)
* Fixed regression in `read_json` where an `Index` would be
returned instead of a `RangeIndex` (#57429)
* Fixed regression in `wide_to_long` raising an AttributeError
for string columns (#57066)
* Fixed regression in `.DataFrameGroupBy.idxmin`,
`.DataFrameGroupBy.idxmax`, `.SeriesGroupBy.idxmin`,
`.SeriesGroupBy.idxmax` ignoring the skipna argument (#57040)
* Fixed regression in `.DataFrameGroupBy.idxmin`,
`.DataFrameGroupBy.idxmax`, `.SeriesGroupBy.idxmin`,
`.SeriesGroupBy.idxmax` where values containing the minimum or
maximum value for the dtype could produce incorrect results
(#57040)
* Fixed regression in `CategoricalIndex.difference` raising