Merge branch '4.4' into 5.2

* 4.4:
  Allow psr/cache v3 but on symfony/cache
  [DI] fix tracking of changes to vendor/ dirs
  Remove EOLed 5.1 branch from PR template
  [HttpKernel] [Kernel] Silence deprecations logs writes
  Update PULL_REQUEST_TEMPLATE.md
  [Mailer][Mime] Update inline part names with newly generated ContentId
  Fixed updating catalogue metadata from intl domain
  [HttpFoundation] Setting `REQUEST_TIME_FLOAT` when constructing a Request object

Author: nicolas-grekas

Authentication/Token/NullToken.php

@@ -94,11 +94,17 @@ public function __unserialize(array $data): void
     {
     }
 
+    /**
+     * @return string
+     */
     public function serialize()
     {
         return '';
     }
 
+    /**
+     * @return void
+     */
     public function unserialize($serialized)
     {
     }