Add changelog note

Author: github-actions[bot]

CHANGELOG.md

@@ -7,6 +7,7 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 ## [UNRELEASED]
 
 - We are rolling out a feature in May/June 2024 that will reduce the Actions cache usage of the Action by keeping only the newest TRAP cache for each language. [#2306](https://github.com/github/codeql-action/pull/2306)
+- Update default CodeQL bundle version to 2.17.4. [#2321](https://github.com/github/codeql-action/pull/2321)
 
 ## 3.25.6 - 20 May 2024