Add changenote for improved version consistency checks

Author: mbg

CHANGELOG.md

@@ -4,7 +4,7 @@ See the [releases page](https://github.com/github/codeql-action/releases) for th
 
 ## [UNRELEASED]
 
-No user facing changes.
+- We have improved the CodeQL Action's ability to validate that the workflow it is used in does not use different versions of the CodeQL Action for different workflow steps. Mixing different versions of the CodeQL Action in the same workflow is unsupported and can lead to unpredictable results. A warning will now be emitted from the `codeql-action/init` step if different versions of the CodeQL Action are detected in the workflow file. Additionally, an error will now be thrown by the other CodeQL Action steps if they load a configuration file that was generated by a different version of the `codeql-action/init` step. [#3099](https://github.com/github/codeql-action/pull/3099) and [#3100](https://github.com/github/codeql-action/pull/3100)
 
 ## 3.30.3 - 10 Sep 2025