docs: use max-age instead of expires

Author: kenjis

user_guide_src/source/libraries/cookies/017.php

@@ -2,15 +2,14 @@
 
 use CodeIgniter\Cookie\Cookie;
 use Config\Services;
-use DateTime;
 
 $response = Services::response();
 
 $cookie = new Cookie(
     'remember_token',
     'f699c7fd18a8e082d0228932f3acd40e1ef5ef92efcedda32842a211d62f0aa6',
     [
-        'expires' => new DateTime('+2 hours'),
+        'max-age' => 3600 * 2, // Expires in 2 hours
     ]
 );
 

user_guide_src/source/libraries/cookies/018.php

@@ -1,15 +1,14 @@
 <?php
 
 use CodeIgniter\Cookie\Cookie;
-use DateTime;
 
 helper('cookie');
 
 $cookie = new Cookie(
     'remember_token',
     'f699c7fd18a8e082d0228932f3acd40e1ef5ef92efcedda32842a211d62f0aa6',
     [
-        'expires' => new DateTime('+2 hours'),
+        'max-age' => 3600 * 2, // Expires in 2 hours
     ]
 );