Add regression test for pivot_table with pivoting tz aware values

Author: Matt Roeschke

doc/source/whatsnew/v0.25.0.rst

@@ -863,6 +863,7 @@ Reshaping
 - Bug in :meth:`Series.nlargest` treats ``True`` as smaller than ``False`` (:issue:`26154`)
 - Bug in :func:`DataFrame.pivot_table` with a :class:`IntervalIndex` as pivot index would raise ``TypeError`` (:issue:`25814`)
 - Bug in :meth:`DataFrame.transpose` where transposing a DataFrame with a timezone-aware datetime column would incorrectly raise ``ValueError`` (:issue:`26825`)
+- Bug in :func:`pivot_table` when pivoting a timezone aware column as the ``values`` would remove timezone information (:issue:`14948`)
 
 Sparse
 ^^^^^^