Add a warning to Release 0.218 about FULL OUTER JOIN regression
Release 0.218
=============
+.. warning::
+
+ This release has the potential to produce incorrect results for three way joins where one of the joins is a ``FULL OUTER JOIN`` and one subquery
+ of the ``FULL OUTER JOIN`` has a ``GROUP BY`` on the join key and some expression that could be evaluated to a constant. For details, please
+ refer to :issue:`12577`.
+
General Changes
---------------
