message: Add `Eq` + `PartialEq` derive for `MetadataVersion`
  Needed for `if version == MetadataVersion::V4 { }`
  in `smart-bench`.
diff: @@ -67,7 +67,7 @@ use serde::{
  /// Versions other than the `Default` are considered deprecated. If you want to
  /// deserialize legacy metadata versions you will need to use an old version of
  /// this crate.
  -#[derive(Debug, Serialize, Deserialize)]
  +#[derive(Debug, Serialize, Deserialize, Eq, PartialEq)]
  pub enum MetadataVersion {
  #[serde(rename = "4")]
  V4,
  