Setting headers blows out default headers.

[dturner34]

https://github.com/evyatarmeged/Humanoid/blob/196f5433ac8383c37492fd3beb57d54b4247120a/src/humanoidReqHandler.js#L74

This line blows out the default header values when passing any header which is probably not expected behavior and it causes humanoid to fail to the cloudflare check, at least in my case. It would be a simple fix to merge objects headers = {...this._getRequestHeaders(url), ...headers}. A temporary/hacky work around for this would be to merge in headers from humanoid._getRequestHeaders(url) before passing them to the request,