add CORS

.hta_slug/dns-tools-get-a-record.php

@@ -1,21 +1,6 @@
 <?php
-header('Content-Type: application/json; charset=utf-8');
-header('Access-Control-Allow-Origin: *');
-header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
-header('Access-Control-Allow-Headers: Content-Type, Authorization');
-header('X-Powered-By: SiliconPin Tools');
-/**
- * DNS A Record Lookup API
- * Endpoint: /dns-tools-get-a-record
- * Method: POST
- * Content-Type: application/json
- */
-
-// -------------------------------
-// Response headers
-// -------------------------------
-header('Content-Type: application/json; charset=utf-8');
-
+    require_once __DIR__ . '/../../hta_config/conf.php';
+    applyApiHeaders($API_HEADERS);
 // -------------------------------
 // Allow only POST
 // -------------------------------