Updated CHANGES for 2.4.1 release
-# 2.x.y (Unreleased)
+# 2.4.1 (2020-03-06)
- [IMPROVED] Record checkpoint on empty `_changes` result in pull replications. This change optimizes
filtered replications when changes in remote database doesn't match the replication filter.
- [UPGRADED] Upgraded to version 2.19.0 of the `cloudant-http` library.
