fix: ipv6 localhost

[chenxsan]

There seems to be a bug in the deprecated url.format() nodejs/node#36654 when formatting ipv6 url:

const url = require('url')
console.log(url.format({
    protocol: 'http',
    hostname: '[::]'
}))

We'll get result of http://[[::]]. Same behavior applies to native-url.

Therefore new SocketClient() would run with url http://[[::]]:8080/sockjs-node when hostname is [::], and that is wrong.

Although they're going to fix it on the Node.js side, but I think it would still make sense to include a quick fix here as it would take some time for native-url to update.

[pmmmwh]

Hey, thanks for the PR! We have had our fair share of "bugs" from native-url for a while now that I'm considering to actually roll our own URL formatting utility (it is not that difficult given that all the heavy lifting had been done by the URL implementation).

I'll leave this open while I decide (and maybe work on that).

Reference route that we could take from Node.js: nodejs/node#28482