Fix deprecated setTimeZoneId

src/Symfony/Component/Form/Extension/Core/ChoiceList/MonthChoiceList.php

@@ -39,8 +39,8 @@ class MonthChoiceList extends PaddedChoiceList
         $pattern = $this->formatter->getPattern();
         $timezone = $this->formatter->getTimezoneId();
 
-        $this->formatter->setTimezoneId('UTC');
-
+        $this->formatter->setTimezone('UTC');
+        
         if (preg_match('/M+/', $pattern, $matches)) {
             $this->formatter->setPattern($matches[0]);
 
@@ -53,6 +53,6 @@ class MonthChoiceList extends PaddedChoiceList
             $this->formatter->setPattern($pattern);
         }
 
-        $this->formatter->setTimezoneId($timezone);
+        $this->formatter->setTimezone($timezone);
     }
 }