docs: add the change log.

Author: ping-yee

user_guide_src/source/changelogs/v4.5.6.rst

@@ -40,6 +40,7 @@ Bugs Fixed
 - **Routing:** Fixed a TypeError in `str_replace()` when `Routing::$translateURIDashes` is set to `true` and a route is defined using a closure.
 
 - **Validation:** Fixed a bug where complex language strings were not properly handled.
+- **CURLRequest:** Added support for handling proxy responses using HTTP versions other than 1.1.
 
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_