BUG: pandas-dev#30740 added to whatsnew

Author: tanmay1618

doc/source/whatsnew/v0.25.3.rst

@@ -10,6 +10,7 @@ including other versions of pandas.
 
 Bug fixes
 ~~~~~~~~~
+- Bug in missing fill_na parameter to DataFrame.unstack() with list of levels (:issue:`30740`)
 
 Groupby/resample/rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^