Update changelog for v3.25.9

Author: github-actions[bot]

CHANGELOG.md

@@ -4,7 +4,7 @@ See the [releases page](https://github.com/github/codeql-action/releases) for th
 
 Note that the only difference between `v2` and `v3` of the CodeQL Action is the node version they support, with `v3` running on node 20 while we continue to release `v2` to support running on node 16. For example `3.22.11` was the first `v3` release and is functionally identical to `2.22.11`. This approach ensures an easy way to track exactly which features are included in different versions, indicated by the minor and patch version numbers.
 
-## [UNRELEASED]
+## 3.25.9 - 12 Jun 2024
 
 - Avoid failing database creation if the database folder already exists and contains some unexpected files. Requires CodeQL 2.18.0 or higher. [#2330](https://github.com/github/codeql-action/pull/2330)
 - The init Action will attempt to clean up the database cluster directory before creating a new database and at the end of the job. This will help to avoid issues where the database cluster directory is left in an inconsistent state. [#2332](https://github.com/github/codeql-action/pull/2332)