docs: add changelog and upgrade

Author: kenjis

user_guide_src/source/changelogs/v4.4.3.rst

@@ -9,6 +9,13 @@ Release Date: Unreleased
     :local:
     :depth: 3
 
+SECURITY
+********
+
+- *Detailed Error Report is Displayed in Production Environment* was fixed.
+  See the `Security advisory GHSA-hwxf-qxj7-7rfj <https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-hwxf-qxj7-7rfj>`_
+  for more information.
+
 BREAKING
 ********
 

user_guide_src/source/installation/upgrade_443.rst

@@ -15,6 +15,14 @@ Please refer to the upgrade instructions corresponding to your installation meth
 Mandatory File Changes
 **********************
 
+error_exception.php
+===================
+
+The following file received significant changes and
+**you must merge the updated versions** with your application:
+
+- app/Views/errors/html/error_exception.php
+
 Breaking Changes
 ****************
 
@@ -48,3 +56,9 @@ This is a list of all files in the **project space** that received changes;
 many will be simple comments or formatting that have no effect on the runtime:
 
 - @TODO
+- app/Config/Boot/development.php
+- app/Config/Boot/production.php
+- app/Config/Boot/testing.php
+- app/Config/Filters.php
+- app/Views/errors/html/error_404.php
+- app/Views/errors/html/error_exception.php