chore: bump signal-hook from 0.3.17 to 0.4.3

Bumps [signal-hook](https://github.com/vorner/signal-hook) from 0.3.17 to 0.4.3.
- [Changelog](https://github.com/vorner/signal-hook/blob/master/CHANGELOG.md)
- [Commits](vorner/signal-hook@v0.3.17...v0.4.3)

---
updated-dependencies:
- dependency-name: signal-hook
  dependency-version: 0.4.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Cargo.lock

@@ -26,7 +26,7 @@ serde = "1" # config parsing, connection header formatting
 serde_derive = "1" # config parsing, connection header formatting
 toml = "0.8" # config parsing
 byteorder = "1" # endianness
-signal-hook = "0.3" # signal handling
+signal-hook = "0.4" # signal handling
 shpool_pty = "0.3.1" # spawning shells in ptys
 lazy_static = "1" # globals
 crossbeam-channel = "0.5" # channels