-`CredentialsError` variants became non-exhaustive. This makes them impossible to construct directly outside of the `aws_types` crate. In order to construct credentials errors, new methods have been added for each variant. Instead of `CredentialsError::Unhandled(...)`, you should instead use `CredentialsError::unhandled`. Matching methods exist for all variants. (#781)
- The default credentials chain now returns `CredentialsError::CredentialsNotLoaded` instead of `ProviderError` when no credentials providers are configured.
- :warning: All Smithy runtime crates have been renamed to have an `aws-` prefix. This may require code changes: