Update itertools requirement from 0.12.0 to 0.13.0

Updates the requirements on [itertools](https://github.com/rust-itertools/itertools) to permit the latest version.
- [Changelog](https://github.com/rust-itertools/itertools/blob/master/CHANGELOG.md)
- [Commits](rust-itertools/itertools@v0.12.0...v0.13.0)

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

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

impl/Cargo.toml

@@ -34,7 +34,7 @@ rustc_version = { version = "0.4", optional = true }
 
 [dev-dependencies]
 derive_more = { path = "..", features = ["full"] }
-itertools = "0.12.0"
+itertools = "0.13.0"
 
 [badges]
 github = { repository = "JelteF/derive_more", workflow = "CI" }