changelog: this is a security release

CHANGES.rst

 Synapse 0.33.1 (2018-08-02)
 ===========================
 
-Bugfixes
---------
+SECURITY FIXES
+--------------
 
 - Fix a potential issue where servers could request events for rooms they have not joined. (`#3641 <https://github.com/matrix-org/synapse/issues/3641>`_)
 - Fix a potential issue where users could see events in private rooms before they joined. (`#3642 <https://github.com/matrix-org/synapse/issues/3642>`_)