Prepare the 3.3.3 release

CHANGELOG

@@ -1,4 +1,4 @@
-# 3.3.3 (2021-XX-XX)
+# 3.3.3 (2021-09-17)
 
  * Allow Symfony 6
  * Improve compatibility with PHP 8.1

src/Environment.php

@@ -38,12 +38,12 @@ use Twig\TokenParser\TokenParserInterface;
  */
 class Environment
 {
-    public const VERSION = '3.3.3-DEV';
+    public const VERSION = '3.3.3';
     public const VERSION_ID = 30303;
     public const MAJOR_VERSION = 3;
     public const MINOR_VERSION = 3;
     public const RELEASE_VERSION = 3;
-    public const EXTRA_VERSION = 'DEV';
+    public const EXTRA_VERSION = '';
 
     private $charset;
     private $loader;