Update signal-hook requirement from 0.3 to 0.4

Updates the requirements on [signal-hook](https://github.com/vorner/signal-hook) to permit the latest version.
- [Changelog](https://github.com/vorner/signal-hook/blob/master/CHANGELOG.md)
- [Commits](vorner/signal-hook@v0.3.0...v0.4.1)

---
updated-dependencies:
- dependency-name: signal-hook
  dependency-version: 0.4.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -48,7 +48,7 @@ async-net = "2.0.0"
 blocking = "1"
 criterion = { version = "0.7", default-features = false, features = ["cargo_bench_support"] }
 getrandom = "0.3"
-signal-hook = "0.3"
+signal-hook = "0.4"
 tempfile = "3"
 
 [target.'cfg(target_os = "linux")'.dev-dependencies]