message: fields of crate_details::Release don't have to be public
diff: @@ -94,9 +94,9 @@ impl ToJson for CrateDetails {
  #[derive(Debug, Eq, PartialEq)]
  struct Release {
  - pub version: String,
  - pub build_status: bool,
  - pub yanked: bool,
  + version: String,
  + build_status: bool,
  + yanked: bool,
  }
  