REL: fix CHANGELOG

CHANGELOG.md

@@ -9,6 +9,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added ###
 
+### Changed ###
+
+### Deprecated ###
+
+### Removed ###
+
+### Fixed ###
+
+### Security ###
+
+## [0.4.0] - 2020-07-17##
+
+### Added ###
+
 * `[Entity|Container].get_property_values` for deeply nested references, e.g.
   from results of SELECT queries.
 * two new `password_method`s for the `pycaosdb.ini` and the