Update CHANGES.md

CHANGES.md

 # Changelog
 
-## 2.1 (unreleased)
--   Move tests directory from ligo/tests to ligo/raven/tests
+## 2.1 (2022-01-18)
+-   Move tests directory from ligo/tests to ligo/raven/tests.
 
--   Fix broken .gitlab-ci.yml build and tests
+-   Fix broken .gitlab-ci.yml build and tests.
 
 -   Add option to calculate coinc far with MDC events.
 
+-   Update dependencies by reducing non-required packages.
+
 
 ## 2.0 (2021-11-09)
 -   Switch to using the gracedb_sdk API instead of gracedb REST. This should