feat(response): add Authorization<Bearer> as a `set`table type
feat(response): add Authorization<Bearer> as a `set`table type

It looks like the Authorization<Bearer> type just didn't exist [1]
at the time the `set` method and `Modifiers` were created [2], but it
has been present since hyper 0.6.0 and would be nice to include here.

[1] -
https://github.com/hyperium/hyper/commit/edf6ac2074d11694ded275807a66df3a8a8e33a6
[2] -
https://github.com/nickel-org/nickel.rs/commit/182517b89a232a715b2fde82efbe507cef96037e

Pull request: #362
Approved by: SimonPersson

anvie/nickel.rs,nickel-org/nickel.rs,jolhoeft/nickel.rs