Patch session fixation vuln

Here's the documentation for that function:
http://php.net/manual/en/function.session-regenerate-id.php

And here's about session fixation:
https://www.owasp.org/index.php/Session_fixation

web/login/index.php

@@ -79,7 +79,9 @@ if (isset($_POST['user']) && isset($_POST['password'])) {
         else {
             $_SESSION['language'] = 'en';
         }
-
+        
+        // Regenerate session id to prevent session fixation
+        session_regenerate_id();
 
         // Redirect request to control panel interface
         if (!empty($_SESSION['request_uri'])) {