Bump changelog and version

CHANGES.rst

@@ -1,3 +1,27 @@
+Changes in synapse v0.21.0-rc3 (2017-05-17)
+===========================================
+
+Features:
+
+* Add per user ratelimiting overrides (PR #2208)
+* Add config option to limit maximum number of events requested by ``/sync``
+  and ``/messages`` (PR #2221) Thanks to @psaavedra!
+
+
+Changes:
+
+* Various small performance fixes (PR #2201, #2202, #2224, #2226, #2227, #2228)
+* Update username availability checker API (PR #2209, #2213)
+* When purging, don't de-delta state groups we're about to delete (PR #2214)
+* Documantation to chek synapse version (PR #2215) Thanks to @hamber-dick!
+* Add an index to event_search to speed up purge history API (PR #2218)
+
+
+Bug fixes:
+
+* Fix API to allow clients to upload one-time-keys with new sigs (PR #2206)
+
+
 Changes in synapse v0.21.0-rc2 (2017-05-08)
 ===========================================
 

synapse/__init__.py

@@ -16,4 +16,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.21.0-rc2"
+__version__ = "0.21.0-rc3"