Bump nix from 0.30.1 to 0.31.1

Bumps [nix](https://github.com/nix-rust/nix) from 0.30.1 to 0.31.1.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.30.1...v0.31.1)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.31.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.lock

@@ -20,7 +20,7 @@ flate2 = "1.1"
 foreign-types = "0.5"
 lexopt = "0.3"
 libc = "0.2"
-nix = { version = "0.30", features = ["event", "feature", "fs", "ioctl", "process", "resource", "sched", "signal", "socket", "time", "user"] }
+nix = { version = "0.31", features = ["event", "feature", "fs", "ioctl", "process", "resource", "sched", "signal", "socket", "time", "user"] }
 rustc-demangle = "0.1"
 zstd = { version = "0.13", default-features = false }