update CHANGELOG.md

Author: dylanljones

CHANGELOG.md

@@ -1,7 +1,7 @@
 # What's New
 
-<a name="unreleased"></a>
-## [Unreleased]
+<a name="v0.4.0"></a>
+## [v0.4.0] - 2025-02-12
 
 This release adds the ability to create new tracks in the Rekordbox v6 database.
 It also adds support for Rekordbox 7 and fixes various bugs.
@@ -610,7 +610,8 @@ This release contains documentation fixes.
 - **add missing djmd tables to `master.db` database documentation**
 
 
-[Unreleased]: https://github.com/dylanljones/pyrekordbox/compare/v0.3.2...HEAD
+[Unreleased]: https://github.com/dylanljones/pyrekordbox/compare/v0.4.0...HEAD
+[v0.4.0]: https://github.com/dylanljones/pyrekordbox/compare/v0.3.2...v0.4.0
 [v0.3.2]: https://github.com/dylanljones/pyrekordbox/compare/v0.3.1...v0.3.2
 [v0.3.1]: https://github.com/dylanljones/pyrekordbox/compare/0.3.0...v0.3.1
 [0.3.0]: https://github.com/dylanljones/pyrekordbox/compare/0.2.3...0.3.0