style: apply cargo fmt workspace-wide

Pure formatting pass from `cargo fmt --all`. No logic changes. Separating
this out so the 1.9 release feature commits that follow show only their
intentional edits.

wfe-buildkit/src/lib.rs

@@ -2,4 +2,4 @@ pub mod config;
 pub mod step;
 
 pub use config::{BuildkitConfig, RegistryAuth, TlsConfig};
-pub use step::{build_output_data, parse_digest, BuildkitStep};
+pub use step::{BuildkitStep, build_output_data, parse_digest};