builder: report error when we can't fetch owner data from crates.io

Author: syphar

crates/bin/docs_rs_builder/src/docbuilder/rustwide_builder.rs

@@ -876,7 +876,9 @@ impl RustwideBuilder {
                             name,
                             &crate_data,
                         ))?,
-                        Err(err) => warn!("{:#?}", err),
+                        Err(err) => {
+                            error!(%name, %version, ?err, "could not fetch crate & owner data");
+                        },
                     }
                 }