Revert change to CHANGES.rst [skip ci]

CHANGES.rst

@@ -6,42 +6,6 @@
 
 .. towncrier release notes start
 
-20.6.3.dev0 (2020-09-22)
-========================
-
-
-Features
---------
-
-- The embedded libev is now asked to detect the availability of
-  ``clock_gettime`` and use the realtime and/or monotonic clocks, if
-  they are available.
-
-  On Linux, this can reduce the number of system calls libev makes.
-  Originally provided by Josh Snyder.
-  See :issue:`issue1648`.
-
-
-Bugfixes
---------
-
-- The ``DummyThread`` objects created automatically by certain
-  operations when the standard library threading module is
-  monkey-patched now match the naming convention the standard library
-  uses ("Dummy-12345"). Previously (since gevent 1.2a2) they used
-  "DummyThread-12345".
-  See :issue:`1659`.
-- Fix compatibility with dnspython 2.
-
-  .. caution:: This currently means that it can be imported. But it
-               cannot yet be used. gevent has a pinned dependency on
-               dnspython < 2 for now.
-  See :issue:`1661`.
-
-
-----
-
-
 20.6.2 (2020-06-16)
 ===================