DOC: Added whatsnew note

Author: s-scherrer

doc/source/whatsnew/v1.1.0.rst

@@ -608,6 +608,7 @@ Groupby/resample/rolling
 - Bug in :meth:`DataFrame.resample` where an ``AmbiguousTimeError`` would be raised when the resulting timezone aware :class:`DatetimeIndex` had a DST transition at midnight (:issue:`25758`)
 - Bug in :meth:`DataFrame.groupby` where a ``ValueError`` would be raised when grouping by a categorical column with read-only categories and ``sort=False`` (:issue:`33410`)
 - Bug in :meth:`GroupBy.first` and :meth:`GroupBy.last` where None is not preserved in object dtype (:issue:`32800`)
+- Bug in :meth:`Rolling.min` and :meth:`Rolling.max` when using a fixed window (:issue:`30726`)
 
 Reshaping
 ^^^^^^^^^