Bump Symfony version to 5.2.9

Author: fabpot

Kernel.php

@@ -74,12 +74,12 @@ abstract class Kernel implements KernelInterface, RebootableInterface, Terminabl
 
     private static $freshCache = [];
 
-    public const VERSION = '5.2.8';
-    public const VERSION_ID = 50208;
+    public const VERSION = '5.2.9-DEV';
+    public const VERSION_ID = 50209;
     public const MAJOR_VERSION = 5;
     public const MINOR_VERSION = 2;
-    public const RELEASE_VERSION = 8;
-    public const EXTRA_VERSION = '';
+    public const RELEASE_VERSION = 9;
+    public const EXTRA_VERSION = 'DEV';
 
     public const END_OF_MAINTENANCE = '07/2021';
     public const END_OF_LIFE = '07/2021';