Prepare the 3.6.1 release

CHANGELOG

@@ -1,4 +1,4 @@
-# 3.6.1 (2023-XX-XX)
+# 3.6.1 (2023-06-08)
 
  * Suppress some native return type deprecation messages
 

src/Environment.php

@@ -40,12 +40,12 @@ use Twig\TokenParser\TokenParserInterface;
  */
 class Environment
 {
-    public const VERSION = '3.6.1-DEV';
+    public const VERSION = '3.6.1';
     public const VERSION_ID = 30601;
     public const MAJOR_VERSION = 3;
     public const MINOR_VERSION = 6;
     public const RELEASE_VERSION = 1;
-    public const EXTRA_VERSION = 'DEV';
+    public const EXTRA_VERSION = '';
 
     private $charset;
     private $loader;