Use modern HTTP parser

[maxharlow]

Currently uses the legacy Node HTTP parser, seen here: https://github.com/maxharlow/reconcile/blob/master/reconcile#L1.

This is because the modern one produces HPE_INVALID_HEADER_TOKEN errors when it receives headers it doesn't expect.

Would be nice to remove this when it's fixed in Node.

[maxharlow]

https://github.com/nodejs/node/blob/master/doc/api/cli.md#--insecure-http-parser
Or nodejs/node#30570