Docs: document the LSP4J update

Author: ForNeVeR

CHANGELOG.md

@@ -14,6 +14,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 ### Added
 - [#184](https://github.com/ant-druha/intellij-powershell/issues/184): Support the null-coalescing operator
 
+### Changed
+- [LSP4J](https://github.com/eclipse-lsp4j/lsp4j) library has been updated to v0.3.1
+
 ## [2.4.0] - 2024-03-09
 ### Changed
 - The lexer and parser were migrated to be auto-generated by the Gradle Grammar-Kit task