Support `host` alias for `hostname`

[valeriangalliat]

Looks like latest request sends options.host instead of options.hostname and this breaks this module, resulting in a socket hang up error:

stream.js:74
      throw er; // Unhandled stream error in pipe.
      ^

Error: socket hang up
    at TLSSocket.onHangUp (_tls_wrap.js:1049:19)
    at TLSSocket.g (events.js:260:16)
    at emitNone (events.js:72:20)
    at TLSSocket.emit (events.js:166:7)
    at endReadableNT (_stream_readable.js:913:12)
    at nextTickCallbackWith2Args (node.js:442:9)
    at process._tickDomainCallback (node.js:397:17)

[mattcg]

Thank you, @valeriangalliat! 👍