build(deps): bump the rust-dependencies group with 4 updates (#12832)

Bumps the rust-dependencies group with 4 updates: [once_cell](https://github.com/matklad/once_cell), [toml](https://github.com/toml-rs/toml), [cc](https://github.com/rust-lang/cc-rs) and [which](https://github.com/harryfei/which-rs).


Updates `once_cell` from 1.20.2 to 1.20.3
- [Changelog](https://github.com/matklad/once_cell/blob/master/CHANGELOG.md)
- [Commits](https://github.com/matklad/once_cell/compare/v1.20.2...v1.20.3)

Updates `toml` from 0.8.19 to 0.8.20
- [Commits](https://github.com/toml-rs/toml/compare/toml-v0.8.19...toml-v0.8.20)

Updates `cc` from 1.2.11 to 1.2.13
- [Release notes](https://github.com/rust-lang/cc-rs/releases)
- [Changelog](https://github.com/rust-lang/cc-rs/blob/main/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/cc-rs/compare/cc-v1.2.11...cc-v1.2.13)

Updates `which` from 7.0.1 to 7.0.2
- [Release notes](https://github.com/harryfei/which-rs/releases)
- [Changelog](https://github.com/harryfei/which-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/harryfei/which-rs/compare/7.0.1...7.0.2)

---
updated-dependencies:
- dependency-name: once_cell
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
- dependency-name: toml
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
- dependency-name: cc
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
- dependency-name: which
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: rust-dependencies
...

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

helix-stdx/Cargo.toml

@@ -18,7 +18,7 @@ ropey.workspace = true
 which = "7.0"
 regex-cursor = "0.1.4"
 bitflags.workspace = true
-once_cell = "1.19"
+once_cell = "1.20"
 regex-automata = "0.4.9"
 unicode-segmentation.workspace = true