Update changelog

CHANGELOG.rst

 Unreleased changes
 ------------------
 
-Version 1
+* Triggered hits plot added
+
+Version 2
 ---------
 
 2.0.0 / 2021-05-05
@@ -17,6 +19,9 @@ Version 1
   instead of crash and annoy
 * Preliminary support for km3pipe v9
 
+Version 1
+---------
+
 
 1.2.0 / 2019-11-25
 ~~~~~~~~~~~~~~~~~~