docs: add changelog

Author: kenjis

user_guide_src/source/changelogs/v4.2.7.rst

@@ -33,6 +33,6 @@ none.
 Bugs Fixed
 **********
 
-none.
+- Fixed a bug that prevents CSP headers from being sent when ``Config\ContentSecurityPolicy::$autoNonce`` is false.
 
 See the repo's `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_ for a complete list of bugs fixed.