release note for pandas-dev#33102

Author: simonjayhawkins

doc/source/whatsnew/v1.0.4.rst

@@ -17,7 +17,7 @@ Fixed regressions
 ~~~~~~~~~~~~~~~~~
 - Bug in :meth:`GroupBy.first` and :meth:`GroupBy.last` where None is not preserved in object dtype (:issue:`32800`)
 - Bug in DataFrame reductions using ``numeric_only=True`` and ExtensionArrays (:issue:`33256`).
-- 
+- Fix performance regression in ``memory_usage(deep=True)`` for object dtype (:issue:`33012`)
 
 .. _whatsnew_104.bug_fixes: