Update CHANGELOG

Author: plemarquand

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## {{releaseVersion}} - {{releaseDate}}
 
+### Added
+
+- When editing .sourcekit-lsp/config.json use the JSON schema from the toolchain ([#1979](https://github.com/swiftlang/vscode-swift/pull/1979))
+
 ### Fixed
 
 - Fix extension failing to activate when Swiftly was installed via Homebrew ([#1975](https://github.com/swiftlang/vscode-swift/pull/1975))