Moved whatsnew to v.0.21.0

Author: rouzazari

doc/source/whatsnew/v0.20.0.txt

@@ -1725,4 +1725,3 @@ Other
 - Compat for 32-bit platforms for ``.qcut/cut``; bins will now be ``int64`` dtype (:issue:`14866`)
 - Bug in interactions with ``Qt`` when a ``QtApplication`` already exists (:issue:`14372`)
 - Avoid use of ``np.finfo()`` during ``import pandas`` removed to mitigate deadlock on Python GIL misuse (:issue:`14641`)
-- Bug in ``DataFrame.rank()`` and ``Series.rank()`` when ``method='dense'`` and ``pct=True`` (:issue:`15630`)

doc/source/whatsnew/v0.21.0.txt

@@ -116,6 +116,7 @@ Reshaping
 
 Numeric
 ^^^^^^^
+- Bug in ``DataFrame.rank()`` and ``Series.rank()`` when ``method='dense'`` and ``pct=True`` (:issue:`15630`)
 
 
 Categorical