`std::error::Error` is not implemented for `eyre::Report<color_eyre::Handler>`

Hi. After updating `eyre` from `0.4.3` to `0.5.0` and `color-eyre` from `0.3.4` to `0.4.1` I'm getting 
```
the trait `std::error::Error` is not implemented for `eyre::Report<color_eyre::Handler>`
```
 when using the `?` operator. I'm not sure if this is a bug or the breaking change implied the version bump. Thanks.