deps(rust): update hostname requirement from ^0.3.1 to ^0.4.0

Updates the requirements on [hostname](https://github.com/svartalf/hostname) to permit the latest version.
- [Release notes](https://github.com/svartalf/hostname/releases)
- [Changelog](https://github.com/svartalf/hostname/blob/master/CHANGELOG.md)
- [Commits](svartalf/hostname@v0.3.1...v0.4.0)

---
updated-dependencies:
- dependency-name: hostname
  dependency-type: direct:production
...

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

src/graph/Cargo.toml

@@ -25,7 +25,7 @@ base64 = { workspace = true }
 chrono = { workspace = true }
 kanidm-hsm-crypto = { workspace = true }
 openssl = { workspace = true }
-hostname = "^0.3.1"
+hostname = "^0.4.0"
 os-release = { workspace = true }
 compact_jwt = { workspace = true }
 jsonwebtoken = { workspace = true }