BUG: to_datetime with Index arg does not retain name in all cases

[mroeschke]

#Example

In [17]: idx = pd.Index([15e9], name='name')

In [18]: pd.to_datetime(idx, errors='ignore', box=True, unit='s').name

In [19]: pd.__version__
Out[19]: '0.24.0.dev0+193.gdc45fba'

There are certain cases where the name attribute of the passed Index are not retained after to_datetime.

The name kwarg looks to be missing from these locations:

pandas/pandas/core/tools/datetimes.py

Line 102 in dc45fba

return Index(result)

pandas/pandas/core/tools/datetimes.py

Line 139 in dc45fba

return Index(tz_results)

pandas/pandas/core/tools/datetimes.py

Line 344 in dc45fba

return Index(result)

[uds5501]

@mroeschke Sir, for adding kwargs, will the following work?

return Index(result ,  {"name": name})

[mroeschke]

Just simply, Index(..., name=name)