fix(docs): updated changelog for app version

CHANGELOG.md

@@ -4,11 +4,20 @@ All notable changes to this project will be documented in this file.
 
 The format is based on Keep a Changelog (https://keepachangelog.com/en/1.0.0/),
 
-## [4.0.0] - tbd
+## [4.0.0] - 2023-08-04
 
 ### Changed
+  - BPDM Pool API: Adapt new data model for easier and more intuitive usage, independent of SaaS data model.
+  - BPDM Gate API: Adapt new data model for easier and more intuitive usage, independent of SaaS data model.
+  - BPDM: Update dependencies to mitigate vulnerabilities in old versions.
 
-- Endpoint for retrieving changelog entries has now improved filtering (breaking API change)
+### Added
+  - BPDM bridge dummy: As new application module.
+  - BPDM: Umbrella Chart with BPDM Bridge Dummy.
+
+### Fixed
+  - BPDM: Deprecated endpoints for retrieving business partners in legacy format.
+  - Endpoint for retrieving changelog entries has now improved filtering (breaking API change)
 
 ## [3.2.2] - 2023-05-12