Merge branch '5.1' into 5.2

* 5.1:
  µCS fix
  CS fix
  CS fix
  [travis] use PHP 8.0 to patch return types and run deps=low
  Add me as a Notifier code owner
  Update sl_SI translations
  Don't trigger deprecation for deprecated aliases pointing to deprecated definitions
  [HttpFoundation] use atomic writes in MockFileSessionStorage
  Make EmailMessage & SmsMessage transport nullable
  remove unused argument
  [DI] fix param annotation
  [Config] Add \Symfony\Component\Config\Loader::load() return type
  Simplify PHP CS Fixer config
  Rename normalize param

Process.php

@@ -1485,8 +1485,8 @@ private function resetProcessData()
         $this->exitcode = null;
         $this->fallbackStatus = [];
         $this->processInformation = null;
-        $this->stdout = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+b');
-        $this->stderr = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+b');
+        $this->stdout = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+');
+        $this->stderr = fopen('php://temp/maxmemory:'.(1024 * 1024), 'w+');
         $this->process = null;
         $this->latestSignal = null;
         $this->status = self::STATUS_READY;