Issue-#3873

Replace deprecated functions with new syntax.

mod/api.php

@@ -1,6 +1,7 @@
 <?php
 
 use Friendica\App;
+use Friendica\Core\Config;
 
 require_once('include/api.php');
 
@@ -60,7 +61,7 @@ function api_content(App $a) {
 			$consumer = new OAuthConsumer($app['client_id'], $app['pw'], $app['redirect_uri']);
 
 			$verifier = md5($app['secret'].local_user());
-			set_config("oauth", $verifier, local_user());
+			Config::set("oauth", $verifier, local_user());
 
 
 			if ($consumer->callback_url!=null) {