Bump version to v1.5.6

Author: aeisenberg

extensions/ql-vscode/CHANGELOG.md

@@ -1,5 +1,7 @@
 # CodeQL for Visual Studio Code: Changelog
 
+## [UNRELEASED]
+
 ## 1.5.5 - 08 September 2021
 
 - Fix bug where a query is sometimes run before the file is saved. [#947](https://github.com/github/vscode-codeql/pull/947)

extensions/ql-vscode/package-lock.json

@@ -4,7 +4,7 @@
   "description": "CodeQL for Visual Studio Code",
   "author": "GitHub",
   "private": true,
-  "version": "1.5.5",
+  "version": "1.5.6",
   "publisher": "GitHub",
   "license": "MIT",
   "icon": "media/VS-marketplace-CodeQL-icon.png",