Backport PR pandas-dev#42686: DOC: 1.3.1 release date

Author: simonjayhawkins

doc/source/whatsnew/v1.3.1.rst

@@ -1,6 +1,6 @@
 .. _whatsnew_131:
 
-What's new in 1.3.1 (July ??, 2021)
+What's new in 1.3.1 (July 25, 2021)
 -----------------------------------
 
 These are the changes in pandas 1.3.1. See :ref:`release` for a full changelog
@@ -43,15 +43,6 @@ Bug fixes
 
 .. ---------------------------------------------------------------------------
 
-.. _whatsnew_131.other:
-
-Other
-~~~~~
--
--
-
-.. ---------------------------------------------------------------------------
-
 .. _whatsnew_131.contributors:
 
 Contributors