Merge branch '6.0' into 6.1

* 6.0:
  restore missing use statement
  [Mime][Security] Fix missing sprintf and add tests
  Remove < PHP 8 dead code

Author: fabpot

Tests/EventListener/SessionListenerTest.php

@@ -14,6 +14,7 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\DependencyInjection\ServiceLocator;
 use Symfony\Component\HttpFoundation\Cookie;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;