Bump indexmap from 2.2.2 to 2.2.6 (#2950)

Bumps [indexmap](https://github.com/indexmap-rs/indexmap) from 2.2.2 to 2.2.6.
- [Changelog](https://github.com/indexmap-rs/indexmap/blob/master/RELEASES.md)
- [Commits](indexmap-rs/indexmap@2.2.2...2.2.6)

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

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

Cargo.toml

@@ -102,7 +102,7 @@ nix = { version = "0.26.4", default-features = false, features = ["term"] }
 
 [build-dependencies]
 anyhow = "1.0.78"
-indexmap = { version = "2.2.2", features = ["serde"] }
+indexmap = { version = "2.2.6", features = ["serde"] }
 itertools = "0.12.1"
 once_cell = "1.18"
 regex = "1.10.2"