Update changelog for v3.29.6

Author: github-actions[bot]

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 See the [releases page](https://github.com/github/codeql-action/releases) for the relevant changes to the CodeQL CLI and language packs.
 
-## [UNRELEASED]
+## 3.29.6 - 07 Aug 2025
 
 - The `cleanup-level` input to the `analyze` Action is now deprecated. The CodeQL Action has written a limited amount of intermediate results to the database since version 2.2.5, and now automatically manages cleanup. [#2999](https://github.com/github/codeql-action/pull/2999)
 - Update default CodeQL bundle version to 2.22.3. [#3000](https://github.com/github/codeql-action/pull/3000)