Update changelog

CHANGELOG.md

@@ -1,3 +1,7 @@
+### [2.2.9] 2022-03-15
+
+  * Fixed regression with plugins that modify install path of packages, [see docs](https://getcomposer.org/doc/articles/plugins.md#plugin-modifies-install-path) if you are authoring such a plugin (#10621)
+
 ### [2.2.8] 2022-03-15
 
   * Fixed `files` autoloading sort order to be fully deterministic (#10617)
@@ -1402,6 +1406,7 @@
 
   * Initial release
 
+[2.2.9]: https://github.com/composer/composer/compare/2.2.8...2.2.9
 [2.2.8]: https://github.com/composer/composer/compare/2.2.7...2.2.8
 [2.2.7]: https://github.com/composer/composer/compare/2.2.6...2.2.7
 [2.2.6]: https://github.com/composer/composer/compare/2.2.5...2.2.6