Bumped Ibexa LTS version to v4.6.21

Author: alongosz

src/contracts/Ibexa.php

@@ -13,5 +13,5 @@ final class Ibexa
     /**
      * Ibexa DXP Version.
      */
-    public const VERSION = '4.6.20';
+    public const VERSION = '4.6.21';
 }