enable service worker on localhost

[Everettss]

We want to debug service worker on localhost. More details in this issue #268

[daliborgogic]

What about IPv6?

const isLocalhost = Boolean(
  location.hostname === 'localhost' ||
  location.hostname === '[::1]' ||
  location.hostname.match(/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/)
)

edited: extra space