Bump indexmap from 2.7.0 to 2.8.0 (#3248)

Bumps [indexmap](https://github.com/indexmap-rs/indexmap) from 2.7.0 to 2.8.0.
- [Changelog](https://github.com/indexmap-rs/indexmap/blob/main/RELEASES.md)
- [Commits](https://github.com/indexmap-rs/indexmap/compare/2.7.0...2.8.0)

---
updated-dependencies:
- dependency-name: indexmap
  dependency-version: 2.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Cargo.toml

@@ -102,7 +102,7 @@ nix = { version = "0.29", default-features = false, features = ["term"] }
 
 [build-dependencies]
 anyhow = "1.0.97"
-indexmap = { version = "2.3.0", features = ["serde"] }
+indexmap = { version = "2.8.0", features = ["serde"] }
 itertools = "0.14.0"
 once_cell = "1.20"
 regex = "1.10.6"