build(deps): update lz-str requirement from 0.1.0 to 0.2.1

Updates the requirements on [lz-str](https://github.com/adumbidiot/lz-str-rs) to permit the latest version.
- [Release notes](https://github.com/adumbidiot/lz-str-rs/releases)
- [Changelog](https://github.com/adumbidiot/lz-str-rs/blob/master/CHANGELOG.md)
- [Commits](adumbidiot/lz-str-rs@0.1.0...v0.2.1)

---
updated-dependencies:
- dependency-name: lz-str
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -46,7 +46,7 @@ anyhow = "1"
 thiserror = "1"
 rayon = "1.5"
 structopt = "0.3"
-lz-str = "0.1.0"
+lz-str = "0.2.1"
 
 [[bin]]
 name = "rbt"