message: Disable 2018->2021 in cargo fix for now, as 2021 lints are not ready.
diff: @@ -699,7 +699,7 @@ impl FixArgs {
  fn next_edition(&self) -> Edition {
  match self.enabled_edition {
  None | Some(Edition::Edition2015) => Edition::Edition2018,
  - Some(Edition::Edition2018) => Edition::Edition2021,
  + Some(Edition::Edition2018) => Edition::Edition2018, // TODO: Change to 2021 when rustc is ready for it.
  Some(Edition::Edition2021) => Edition::Edition2021,
  }
  }
  