Fix clippy issues in a KeyProvisioner

web-client/src/lib.rs

             let keys: Vec<(PublicKey, String)> = participants_keys
                 .into_iter()
                 .map(|(pk, participant_id)| {
-                    base64::decode(&pk)
+                    base64::decode(pk)
                         .map(|it| (it, participant_id))
                         .map_err(|err| ApiError::new(ErrorType::Other, err.to_string()))
                         .and_then(|(pk_bytes, participant_id)| {