Update CHANGELOG.md: 0.4.0

Author: victorpopkov

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased][]
 
+## [0.4.0][] - 2020-09-21
+
 ### Added
 
 - Locale text scale in the front-end data sidebar
@@ -54,6 +56,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 First release.
 
-[unreleased]: https://github.com/victorpopkov/dst-mod-dev-tools/compare/v0.3.0...HEAD
+[unreleased]: https://github.com/victorpopkov/dst-mod-dev-tools/compare/v0.4.0...HEAD
+[0.4.0]: https://github.com/victorpopkov/dst-mod-dev-tools/compare/v0.3.0...v0.4.0
 [0.3.0]: https://github.com/victorpopkov/dst-mod-dev-tools/compare/v0.2.0...v0.3.0
 [0.2.0]: https://github.com/victorpopkov/dst-mod-dev-tools/compare/v0.1.0...v0.2.0