Update changelog

Author: josemmo

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Switched project to Astral's uv project manager.
+- Switched documentation generator from Sphinx to MkDocs.
 - Added new `Element`, `Project`, and `IfcUUID` classes.
 - Added `ElementType` enumeration to be used with `Element.type` property.
 - Added initial `Beam` and `Wall` classes.