Update itertools requirement from 0.11.0 to 0.12.0 (#574)

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](https://github.com/rust-itertools/itertools/compare/v0.11.0...v0.12.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

frost-core/Cargo.toml

@@ -35,7 +35,7 @@ serdect = { version = "0.2.0", optional = true }
 thiserror = "1.0"
 visibility = "0.1.0"
 zeroize = { version = "1.5.4", default-features = false, features = ["derive"] }
-itertools = "0.11.0"
+itertools = "0.12.0"
 
 # Test dependencies used with the test-impl feature
 proptest = { version = "1.0", optional = true }