DOC: update CHANGELOG

CHANGELOG.md

@@ -5,11 +5,24 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-
 ## [Unreleased] ##
 
 ### Added ###
 
+### Changed ###
+
+### Deprecated ###
+
+### Removed ###
+
+### Fixed ###
+
+### Security ###
+
+## 3.0.0 (2020-09-01) ##
+
+### Added ###
+
 * New `feature_config` table for storing configuration of features as key-value
   pairs. Currently only used by the ENTITY_VERSIONING feature for switching
   versioning on or off. Convenient function `is_feature_config` for checking