fix: docker page: switch to coupon service

Author: morrolinux

docker.php

@@ -56,7 +56,7 @@
     //UDEMY COUPONS
     $archlinux = $DPCM = "";
 
-    $json_data = file_get_contents('udemy_coupons.json');
+    $json_data = file_get_contents('http://udemy-coupon-dump');
     $data = json_decode($json_data, true);
 
     $DPCM = $data["Docker"];