Prepare for the 1.5.7 release (#1016)

Author: aeisenberg

extensions/ql-vscode/CHANGELOG.md

@@ -1,8 +1,8 @@
 # CodeQL for Visual Studio Code: Changelog
 
-## [UNRELEASED]
+## 1.5.7 - 23 November 2021
 
-- Fix the _CodeQL: Open Referenced File_ command for Windows systems. [#979](https://github.com/github/vscode-codeql/pull/979) 
+- Fix the _CodeQL: Open Referenced File_ command for Windows systems. [#979](https://github.com/github/vscode-codeql/pull/979)
 - Support large SARIF results files (>4GB) without crashing VS Code. [#1004](https://github.com/github/vscode-codeql/pull/1004)
 - Fix a bug that shows 'Set current database' when hovering over the currently selected database in the databases view. [#976](https://github.com/github/vscode-codeql/pull/976)
 - Fix a bug with importing large databases. Databases over 4GB can now be imported directly from LGTM or from a zip file. This functionality is only available when using CodeQL CLI version 2.6.0 or later. [#971](https://github.com/github/vscode-codeql/pull/971)