Allow adding custom headers on static projects

im trying to make a realtime npm package update website using the static projects, but it refuses to connect to anything except the glitch project itself because its missing CORS headers

this is the url for realtime npm updates that im trying to use https://skimdb.npmjs.com/_changes?feed=continuous&heartbeat=10000&since=now but it requires “Access-Control-Allow-Origin” for it to work