Backport PR #48642 on branch 1.5.x (DOC: Add release notes for 1.5.1) (#48647)

Backport PR #48642: DOC: Add release notes for 1.5.1 Co-authored-by: Patrick Hoefler <61934744+phofl@users.noreply.github.com>

Author: meeseeksmachine

doc/source/whatsnew/index.rst

@@ -16,6 +16,7 @@ Version 1.5
 .. toctree::
  :maxdepth: 2
 
+ v1.5.1
  v1.5.0
 
 Version 1.4

doc/source/whatsnew/v1.5.1.rst

@@ -0,0 +1,43 @@
+.. _whatsnew_151:
+
+What's new in 1.5.1 (October ??, 2022)
+--------------------------------------
+
+These are the changes in pandas 1.5.1. See :ref:`release` for a full changelog
+including other versions of pandas.
+
+{{ header }}
+
+.. ---------------------------------------------------------------------------
+
+.. _whatsnew_151.regressions:
+
+Fixed regressions
+~~~~~~~~~~~~~~~~~
+-
+-
+
+.. ---------------------------------------------------------------------------
+
+.. _whatsnew_151.bug_fixes:
+
+Bug fixes
+~~~~~~~~~
+-
+-
+
+.. ---------------------------------------------------------------------------
+
+.. _whatsnew_151.other:
+
+Other
+~~~~~
+-
+-
+
+.. ---------------------------------------------------------------------------
+
+.. _whatsnew_151.contributors:
+
+Contributors
+~~~~~~~~~~~~