chore(deps): update petgraph requirement from ^0.7.1 to ^0.8.0 (#46)

Updates the requirements on [petgraph](https://github.com/petgraph/petgraph) to permit the latest version.
- [Release notes](https://github.com/petgraph/petgraph/releases)
- [Changelog](https://github.com/petgraph/petgraph/blob/master/CHANGELOG.md)
- [Commits](https://github.com/petgraph/petgraph/compare/petgraph@v0.7.1...petgraph@v0.8.0)

---
updated-dependencies:
- dependency-name: petgraph
  dependency-version: 0.8.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -41,7 +41,7 @@ itertools = "^0.14.0"
 num-bigint = "^0.4.6"
 num-traits = "^0.2.19"
 pacmanconf = "^3.0.0"
-petgraph = "^0.7.1"
+petgraph = "^0.8.0"
 pipe-trait = "^0.4.0"
 rayon = "^1.10.0"
 reflink = "^0.1.3"