Rename CHANGELOG to CHANGELOG.md

Author: bogdan-d

CHANGELOG renamed to CHANGELOG.md

@@ -17,4 +17,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Support for send actions
 - Support for partial user update
 - Support for sending files
-- Support for invite members
+- Support for invite members