Added release note to issue 14401 resolve.

Author: Nicholas Ver Halen

doc/source/whatsnew/v0.19.1.txt

@@ -48,3 +48,4 @@ Bug Fixes
 - Bug in ``MultiIndex.set_levels`` where illegal level values were still set after raising an error (:issue:`13754`)
 - Bug in ``DataFrame.to_json`` where ``lines=True`` and a value contained a ``}`` character (:issue:`14391`)
 - Bug in ``df.groupby`` causing an ``AttributeError`` when grouping a single index frame by a column and the index level (:issue`14327`)
+- Bug in ``pd.to_numeric`` where it would not downcast a 0 to a uint8 (:issue:`14404`)