Add note that the project is broken in 0.12.x

Hopefully we can get rid of this soon!

README.md

@@ -5,6 +5,14 @@
 [![Coverage](https://img.shields.io/coveralls/request/request.svg?style=flat)](https://coveralls.io/r/request/request)
 [![Gitter](https://img.shields.io/badge/gitter-join_chat-blue.svg?style=flat)](https://gitter.im/request/request?utm_source=badge)
 
+## :siren: Does not work with Node v0.12.x :siren:
+
+We're working on this.  Want to help?  See the
+[contribution guidelines](https://github.com/request/request/blob/master/CONTRIBUTING.md),
+help us fix the
+[failing tests](https://travis-ci.org/request/request/jobs/49916823),
+and [submit a PR](https://github.com/request/request/pulls)!
+
 ## Super simple to use
 
 Request is designed to be the simplest way possible to make http calls. It supports HTTPS and follows redirects by default.