Update itertools requirement from 0.7 to 0.8
Update itertools requirement from 0.7 to 0.8

Updates the requirements on [itertools](https://github.com/bluss/rust-itertools) to permit the latest version.
- [Release notes](https://github.com/bluss/rust-itertools/releases)
- [Commits](https://github.com/bluss/rust-itertools/commits/0.8.0)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
brendanzab/codespan