cors middleware update

add Content-Type and User-Agent to Access-Control-Allow-Headers
this change is helping cors issue from latest browsers

Author: malisetti

lib/middleware/cors.js

@@ -22,7 +22,8 @@ function cors() {
     res.setHeader(
       'Access-Control-Allow-Methods',
       'GET,HEAD,PUT,PATCH,POST,DELETE');
-    res.setHeader('Access-Control-Allow-Headers', 'Authorization');
+    res.setHeader(
+      'Access-Control-Allow-Headers', 'Authorization,Content-Type,User-Agent');
 
     if (req.method === 'OPTIONS') {
       res.setStatus(200);