fix: remove use of the deprecated OutgoingMessage.prototype._headers
fix: remove use of the deprecated OutgoingMessage.prototype._headers

Removes deprecated code. Cannot replace with setHeaders since headers already sent.
In case you still want to obscure the headers from the request-object i suggest you strip down the request object to only include desired attributes, rather than changing the original object.

Co-authored-by: Marco Link <b412850424996c7a30fcfead24f4f281825c3a16@contentful.com>
Co-authored-by: Makinwa Olubukola <c8d8a65a0e281b0697efa23e67e66ce623368b86@contentful.com>
contentful/contentful.js