Update pretty requirement from ~0.10 to ~0.12

Updates the requirements on [pretty](https://github.com/Marwes/pretty.rs) to permit the latest version.
- [Release notes](https://github.com/Marwes/pretty.rs/releases)
- [Changelog](https://github.com/Marwes/pretty.rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Marwes/pretty.rs/compare/v0.10.0...v0.12.0)

---
updated-dependencies:
- dependency-name: pretty
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

edn/Cargo.toml

@@ -14,7 +14,7 @@ chrono = "~0.4"
 itertools = "~0.10"
 num = "~0.4"
 ordered-float = "~2.8"
-pretty = "~0.10"
+pretty = "~0.12"
 uuid = { version = "~1.0", features = ["v4", "serde"] }
 serde = { version = "~1.0", optional = true }
 serde_derive = { version = "~1.0", optional = true }