Set gix to 0.56 (#261)

* Bump gix from 0.55.2 to 0.56.0

Bumps [gix](https://github.com/Byron/gitoxide) from 0.55.2 to 0.56.0.
- [Release notes](https://github.com/Byron/gitoxide/releases)
- [Changelog](https://github.com/Byron/gitoxide/blob/main/CHANGELOG.md)
- [Commits](GitoxideLabs/gitoxide@gix-v0.55.2...gix-v0.56.0)

---
updated-dependencies:
- dependency-name: gix
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

* Restrict `gix` version range

* Fix `gix` `at_path` usage

---------

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