chore(deps): bump indexmap from 2.10.0 to 2.12.0 in /codex-rs

Bumps [indexmap](https://github.com/indexmap-rs/indexmap) from 2.10.0 to 2.12.0.
- [Changelog](https://github.com/indexmap-rs/indexmap/blob/main/RELEASES.md)
- [Commits](indexmap-rs/indexmap@2.10.0...2.12.0)

---
updated-dependencies:
- dependency-name: indexmap
  dependency-version: 2.12.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

codex-rs/Cargo.lock

@@ -127,7 +127,7 @@ icu_decimal = "2.0.0"
 icu_locale_core = "2.0.0"
 ignore = "0.4.23"
 image = { version = "^0.25.8", default-features = false }
-indexmap = "2.6.0"
+indexmap = "2.12.0"
 insta = "1.43.2"
 itertools = "0.14.0"
 keyring = "3.6"