message: Use Rust 2021 edition with `rustfmt` in CI
  We've long migrated to the 2021 edition everywhere. See PRs
  and
  See issue too.
diff: @@ -11,7 +11,7 @@ sdk-lints check --all
  sdk-lints fix --all
  # shellcheck disable=SC2046
  -rustfmt --check --edition 2018 $(find . -name '*.rs' -print | grep -v /target/)
  +rustfmt --check --edition 2021 $(find . -name '*.rs' -print | grep -v /target/)
  ./gradlew -p buildSrc test
  ./gradlew ktlint
  