Add IPv6 loopback address

This fixes using broccoli locally with nodejs 18.x. Since node 17.x it
favours IPv6 over IPv4: nodejs/node#40537

lib/middleware.js

@@ -112,7 +112,7 @@ module.exports = function getMiddleware(watcher, options) {
       if(request.headers.origin) {
         // Check if origin resolves to a loopback IP, only add CORS headers if that's the case.
         dns.lookup(url.parse(request.headers.origin).hostname, function(err, address) {
-          if(!err && address === '127.0.0.1') {
+          if(!err && (address === '127.0.0.1' || address === '::1')) {
             response.setHeader('Access-Control-Allow-Origin', request.headers.origin)
             writeResponse()
           }