message: Don't need extern crate in 2018
diff: @@ -35,6 +35,7 @@ crates:
  name = "hello_world"
  version = "0.1.0"
  authors = ["Your Name <you@example.com>"]
  +edition = "2018"
  [dependencies]
  time = "0.1.12"
  @@ -68,11 +69,9 @@ these dependencies we used.
  Now, if `regex` gets updated, we will still build with the same revision until
  we choose to `cargo update`.
  -You can now use the `regex` library using `extern crate` in `main.rs`.
  +You can now use the `regex` library in `main.rs`.
  ```rust
  -extern crate regex;
  -
  use regex::Regex;
  fn main() {
  