Update changelog for v2.1.28

Author: github-actions[bot]

CHANGELOG.md

@@ -1,6 +1,6 @@
 # CodeQL Action Changelog
 
-## [UNRELEASED]
+## 2.1.28 - 18 Oct 2022
 
 - Update default CodeQL bundle version to 2.11.1. [#1294](https://github.com/github/codeql-action/pull/1294)
 - Replace uses of GitHub Actions command `set-output` because it is now deprecated. See more information in the [GitHub Changelog](https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/). [#1301](https://github.com/github/codeql-action/pull/1301)