fix: remove improper use of map when getting headers

Signed-off-by: Guillaume Deslandes <[email protected]>

addon/uploaders/uploader.js

@@ -123,7 +123,7 @@ export default EmberObject.extend(Evented, {
  const headers = {};
  xhr
  .getAllResponseHeaders().trim().split(/[\r\n]+/)
- .map((header) => {
+ .forEach((header) => {
  const [key, value] = header.split(': ');
  headers[key] = value;
  }),