Assistant v2 update

Author: jpsilvaa

src/ServiceProvider.php

@@ -33,7 +33,7 @@ public function register(): void
             return OpenAI::factory()
                 ->withApiKey($apiKey)
                 ->withOrganization($organization)
-                ->withHttpHeader('OpenAI-Beta', 'assistants=v1')
+                ->withHttpHeader('OpenAI-Beta', 'assistants=v2')
                 ->withHttpClient(new \GuzzleHttp\Client(['timeout' => config('openai.request_timeout', 30)]))
                 ->make();
         });