Add migration notes for Configure attribute

Author: othercorey

en/appendices/5-3-migration-guide.rst

@@ -74,6 +74,21 @@ Command
 - ``cake server`` now supports a ``--frankenphp`` option that will start the
   development server with `FrankenPHP <https://frankenphp.dev/>`__.
 
+Core
+----
+
+- Added ``Configure`` container attribute to support injecting ``Configure`` values into
+  constructor promoted properties when resolving a class. Example:
+
+  .. code-block:: php
+
+    class InjectedService
+    {
+        public function __construct(
+            #[Configure('MyService.apiKey')] protected string $apiKey,
+        ) { }
+    }
+
 Cache
 -----