fix: allow for brackets IPv6 addresses

This will allow phin and pactum to both use IPv6 addresses in their calls. Useful for when NestJS's app.getUrl() returns http://[::1]:3000 or similar. This should not impact anything else, as [ and ] are invalid host characters otherwise

fix #14

Any chance that this could get reviewed and merged upstream to help out phin and pactum? Thanks

@ethanent apologies for the ping, but do you think this could get reviewed and merged up for phin?

Thanks!