chore: update phoenix configuration

`:namespace` config is deprecated, moved to `:formats` configuration

Signed-off-by: Luca Zaninotto <luca.zaninotto@secomind.com>

Author: lusergit

backend/lib/edgehog_web.ex

@@ -1,7 +1,6 @@
-#
 # This file is part of Edgehog.
 #
-# Copyright 2021-2023 SECO Mind Srl
+# Copyright 2021-2026 SECO Mind Srl
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,7 +15,6 @@
 # limitations under the License.
 #
 # SPDX-License-Identifier: Apache-2.0
-#
 
 defmodule EdgehogWeb do
   @moduledoc """
@@ -41,7 +39,7 @@ defmodule EdgehogWeb do
   def controller do
     quote do
       use Gettext, backend: EdgehogWeb.Gettext
-      use Phoenix.Controller, namespace: EdgehogWeb
+      use Phoenix.Controller, formats: [json: "View"]
 
       import Plug.Conn