Bumps [rustix](https://github.com/bytecodealliance/rustix) from 0.38.18 to 0.38.21.
- [Release notes](https://github.com/bytecodealliance/rustix/releases)
- [Commits](bytecodealliance/rustix@v0.38.18...v0.38.21)

---
updated-dependencies:
- dependency-name: rustix
  dependency-type: indirect
...

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

Release was made by a trusted author.

This switches the underlying implementation to use the libc crate
instead of rustix, which ends up removing the rustix dependency entirely
(outside of dev deps).

Also is-terminal has been merged into Rust itself and will go away
whenever there's a new lalrpop release we can update to.