fix: change the implementation way and add the changelog.

Author: ping-yee

system/Database/Postgre/Connection.php

@@ -150,7 +150,8 @@ private function convertDSN()
     public function reconnect()
     {
         if ($this->connID === false || pg_ping($this->connID) === false) {
-            $this->connect();
+            $this->close();
+            $this->initialize();
         }
     }
 

user_guide_src/source/changelogs/v4.5.6.rst

@@ -41,6 +41,8 @@ Bugs Fixed
 
 - **Routing:** Fixed a TypeError in `str_replace()` when `Routing::$translateURIDashes` is set to `true` and a route is defined using a closure.
 
+- **PostgreSQL Connection:** Fixed bug that PostgreSQL cannot reconnect the database with ``reconnect()`` method.
+
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_
 for a complete list of bugs fixed.