[ci skip] Update codeigniter.com links to https
diff --git a/system/helpers/captcha_helper.php b/system/helpers/captcha_helper.php
index 4d8e98e..db708e8 100644
--- a/system/helpers/captcha_helper.php
+++ b/system/helpers/captcha_helper.php
@@ -31,7 +31,7 @@
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
  * @copyright	Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
- * @link	http://codeigniter.com
+ * @link	https://codeigniter.com
  * @since	Version 1.0.0
  * @filesource
  */
@@ -44,7 +44,7 @@
  * @subpackage	Helpers
  * @category	Helpers
  * @author		EllisLab Dev Team
- * @link		http://codeigniter.com/user_guide/helpers/captcha_helper.html
+ * @link		https://codeigniter.com/user_guide/helpers/captcha_helper.html
  */
 
 // ------------------------------------------------------------------------