BUG: astype of datetimelike to non-NS #19223
Description
The current pandas master includes a behaviour change date conversion.
Before #19176
In [1]: import pandas as pd In [2]: pd.DataFrame({'x': [3, 2, 1]}).astype('M8[us]') Out[2]: x 0 1970-01-01 00:00:00.000003 1 1970-01-01 00:00:00.000002 2 1970-01-01 00:00:00.000001 After #19176
In [1]: import pandas as pd In [2]: pd.DataFrame({'x': [3, 2, 1]}).astype('M8[us]') Out[2]: x 0 1970-01-01 00:00:00.000000003 1 1970-01-01 00:00:00.000000002 2 1970-01-01 00:00:00.000000001