Merge pull request #20 from chadha/RadioVoterFixPsalm

RadioVoter fix psalm

Author: elbcoast

Voters/RatioVoter.php

@@ -23,7 +23,7 @@ class RatioVoter implements VoterInterface
     use VoterTrait;
 
     /**
-     * @var SessionInterface
+     * @var SessionInterface|null
      */
     protected $session;
 
@@ -40,7 +40,7 @@ class RatioVoter implements VoterInterface
     /**
      * @param SessionInterface|null $session
      */
-    public function __construct(SessionInterface $session = null)
+    public function __construct(?SessionInterface $session = null)
     {
         $this->session = $session;
     }