Allow spdy to be used as webpack dev server.

[Hyperkid123]

Changes

• update webpack and its dependencies to latest versions
• enable setting the _unstableSpdy option from fec.config.js to enable spdy as a dev server

[nacho-bot]

                      :soon::shipit::octocat:      :rose:Shipit Squirrel has this release minor surrounded, be ready for a new version:sunflower:

[nacho-bot]

     🌱 🌸 🌷 🌻 🌟 New version of package has been released 🌟 🌻 🌷 🌸 🌱

                The release is available on:

        :package:@redhat-cloud-services/frontend-components-config/v/6.3.0:package:

             :boom:This feature is brought to you by probot:rocket: