Update changelog for 4.4.0 (#2988)

Author: GromNaN

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
-## [4.4.0] - unreleased
+## [4.4.0] - 2024-05-31
 
 * Support collection name prefix by @GromNaN in [#2930](https://github.com/mongodb/laravel-mongodb/pull/2930)
 * Ignore `_id: null` to let MongoDB generate an `ObjectId` by @GromNaN in [#2969](https://github.com/mongodb/laravel-mongodb/pull/2969)