Better error reporting when GitHub responds with an unsuspected status code

[burtonjc]

Currently, there is a white list of response codes that will be handled by Octonode. Anything outside of that list gets a generic failure message. For example, updating an issue would say "Issue update error". One of our services is getting a substantial number of these errors and we don't have any insight as to why because Octonode is swallowing GitHub's response.

Any chance that generic condition could still report the status code and body?

[burtonjc]

Also, my guess is GitHub is responding with 3xx status codes (which aren't accounted for by octonode). The request npm module follows redirects by default, so I would think it should still just work. But it does look like some redirect fixes have gone into the request module since the version octonode is using. Might be helpful to bump the request version.