README stylistic fix

Author: Val

README.md

@@ -62,7 +62,7 @@ module.exports = {
         host: 'localhost',
         port: 3000,
         // proxy the Webpack Dev Server endpoint
-        // (which is serving on http://localhost:3100/)
+        // (which should be serving on http://localhost:3100/)
         // through BrowserSync
         proxy: 'http://localhost:3100/'
       },