the `?` operator can only be applied to values that implement `Try`

Hi, looks like you have problem in your code:

```rust
error[E0277]: the `?` operator can only be applied to values that implement `Try`
--> /home/batman/.cargo/registry/src/github.com-1ecc6299db9ec823/danger-0.1.0/src/bin/update_types.rs:17:18
|
17 | let mut resp = reqwest::get(url)?;
| ^^^^^^^^^^^^^^^^^^ the `?` operator cannot be applied to type `impl Future>`
|
= help: the trait `Try` is not implemented for `impl Future>`

For more information about this error, try `rustc --explain E0277`.`