Updating CHANGELOG for 0.21.0 release.
diff --git a/CHANGELOG b/CHANGELOG
index 7cece48..8dd9ee9 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,6 @@
+Aurora 0.21.0
+--------------------------------------------------------------------------------
+
 Aurora 0.20.0
 --------------------------------------------------------------------------------
 ## Bug