* Change the Parquet library used by Pandas to allow choice of PyArrow or fastparquet 343
The PyArrow dependency is no longer required in the extra package Pandas.
If you use the unload option, you must install the extra package with `PyAthena[Arrow]` or `PyAthena[fastparquet]`.
Thanks aaronclong 341
* Change the default value of na_values in AsyncPandasCursor from None to empty character 347
Thanks dblado 346
* Support for specifying ExternalId in AssumeRole 348
Thanks dblado 344