deps: update to http-parser 2.7.0

Adds `2` as a return value of `on_headers_complete`, this mode will be
used to fix handling responses to `CONNECT` requests.

See: https://github.com/nodejs/node/pull/6198
PR-URL: https://github.com/nodejs/node/pull/6279


Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: James M Snell <jasnell@gmail.com>