[Python] to_pandas conversion removes timezone from type

>>> import pyarrow as pa
>>> a = pa.array([1], type=pa.timestamp('us', tz='America/Los_Angeles'))
>>> a.to_pandas()
0   1970-01-01 00:00:00.000001
dtype: datetime64[ns]

In [4]: import pyarrow as pa 
   ...: a = pa.array([1], type=pa.timestamp('us', tz='America/Los_Angeles'))  
   ...: c = pa.Column.from_array('ts', a) 

In [5]: c.to_pandas()                                                                                                        
Out[5]: 
0   1969-12-31 16:00:00.000001-08:00
Name: ts, dtype: datetime64[ns, America/Los_Angeles]