Get rid of deprecated method calls

app/Client/Http/Modifiers/CheckBasicAuthentication.php

@@ -3,6 +3,7 @@
 namespace App\Client\Http\Modifiers;
 
 use App\Client\Configuration;
+use GuzzleHttp\Psr7\Message;
 use GuzzleHttp\Psr7\Response;
 use function GuzzleHttp\Psr7\str;
 use Illuminate\Support\Arr;
@@ -29,7 +30,7 @@ class CheckBasicAuthentication
 
         if (is_null($username)) {
             $proxyConnection->send(
-                str(new Response(401, [
+                Message::toString(new Response(401, [
                     'WWW-Authenticate' => 'Basic realm=Expose',
                 ], 'Unauthorized'))
             );