Add Response to the globals list

For some reason Response is not being recognised even though it is part of
Javascript (https://caniuse.com/?search=Response). This is possibly due to out
of date dependencies preventing ES6 coding standards being checkd.

It is added to the list of globals to allow `yarn standard` to pass. It may be
possible to remove this after refactoring.

package.json

@@ -79,11 +79,12 @@
     "globals": [
       "GOVUK",
       "moj",
-      "Stickyfill"
+      "Stickyfill",
+      "Response"
     ],
     "ignore": [
       "app/webpack/javascripts/vendor/",
       "spec/javascripts/helpers/"
     ]
   }
-}
+}