docs: Update changelog for version 1.4.0

Author: pawamoy

CHANGELOG.md

@@ -6,6 +6,18 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 <!-- insertion marker -->
+## [1.4.0](https://github.com/mkdocstrings/handler-template/releases/tag/1.4.0) - 2025-03-12
+
+<small>[Compare with 1.3.0](https://github.com/mkdocstrings/handler-template/compare/1.3.0...1.4.0)</small>
+
+### Features
+
+- Update for latest mkdocstrings ([b4959f4](https://github.com/mkdocstrings/handler-template/commit/b4959f469b1fe16c0771eaefb1f5bc453ad6309c) by Timothée Mazzucotelli).
+
+### Code Refactoring
+
+- Move last public module to internal folder ([451735d](https://github.com/mkdocstrings/handler-template/commit/451735da2dc78fc29de2e2f3be27976b8e7aab04) by Timothée Mazzucotelli).
+
 ## [1.3.0](https://github.com/mkdocstrings/handler-template/releases/tag/1.3.0) - 2025-03-11
 
 <small>[Compare with 1.2.4](https://github.com/mkdocstrings/handler-template/compare/1.2.4...1.3.0)</small>