Add changes to changelog

Co-authored by: Marc Jaramillo mnj.webdeveloper@gmail.com
Co-authored by: Musab Guma'a mgsium@github.com

Author: marcnjaramillo

extensions/ql-vscode/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [UNRELEASED]
 
+- Use the CodeQL CLI command `database unbundle` for the archive download option, which ensures even archives over 4GB in size can be downloaded. [#971](https://github.com/github/vscode-codeql/pull/971)
+
 - Replace certain control codes (`U+0000` - `U+001F`) with their corresponding control labels (`U+2400` - `U+241F`)  in the results view. [#963](https://github.com/github/vscode-codeql/pull/963)
 
 ## 1.5.6 - 07 October 2021