TST: Add entry in whatsnew

Author: nrebena

doc/source/whatsnew/v1.1.3.rst

@@ -36,6 +36,7 @@ Fixed regressions
 - Fixed regression in :meth:`read_excel` with ``engine="odf"`` caused ``UnboundLocalError`` in some cases where cells had nested child nodes (:issue:`36122`,:issue:`35802`)
 - Fixed regression in :class:`DataFrame` and :class:`Series` comparisons between numeric arrays and strings (:issue:`35700`,:issue:`36377`)
 - Fixed regression when setting empty :class:`DataFrame` column to a :class:`Series` in preserving name of index in frame (:issue:`36527`)
+- Fixed regression in :class:`Period` incorrect value for ordinal over the maximum timestamp (:issue:`36430`)
 
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