Merge branch '5.0'

* 5.0:
  updated VERSION for 3.4.40
  update CONTRIBUTORS for 3.4.40
  updated CHANGELOG for 3.4.40
  [WebProfilerBundle] changed label of peak memory usage in the time & memory panels (MB into MiB)
  add tests for the ConstraintViolationBuilder class
  Improve dirname usage
  [PhpUnitBridge] Use COMPOSER_BINARY env var if available
  Allow invalidateTags calls to be traced by data collector
  [YAML] escape DEL(\x7f)
  fix compatibility with phpunit 9
  [Cache] skip APCu in chains when the backend is disabled
  [Mailer] Add a comment to avoid more wrong PRs on this piece of code
  [Form] apply automatically step=1 for datetime-local input
  remove getContainer overwrites in tests
  Fixing a bug where class_alias would cause incorrect items in debug:autowiring
  [DependencyInjection][ServiceSubscriber] Support late aliases
  Fix profiler nullable string type

Author: nicolas-grekas

Profiler/Profile.php

@@ -101,7 +101,7 @@ public function getIp()
         return $this->ip;
     }
 
-    public function setIp(string $ip)
+    public function setIp(?string $ip)
     {
         $this->ip = $ip;
     }
@@ -131,7 +131,7 @@ public function getUrl()
         return $this->url;
     }
 
-    public function setUrl(string $url)
+    public function setUrl(?string $url)
     {
         $this->url = $url;
     }