Update changelog

Author: davidshepherd7

Diff for: README.md

@@ -190,6 +190,8 @@ to be too heavy to add to electric-spacing.
 
 ### Unstable
 
+### Version 2.1
+
 * Fix treating comint-based modes (typically called inferior-...) as plain text
   modes by default.
 * Apply default python rules to inferior-python-mode, and similiarly for R.