message: chore(*): enable `#[deny(warnings)]` at only testing
diff: #![doc(html_root_url = "https://docs.rs/hyper/0.12.7")]
  #![deny(missing_docs)]
  -#![deny(warnings)]
  #![deny(missing_debug_implementations)]
  +#![cfg_attr(test, deny(warnings))]
  #![cfg_attr(all(test, feature = "nightly"), feature(test))]
  //! # hyper
  