Update sev requirement

Updates the requirements on [sev](https://github.com/virtee/sev) to permit the latest version.

Updates `sev` to 5.0.0
- [Commits](virtee/sev@v4.0.0...v5.0.0)

---
updated-dependencies:
- dependency-name: sev
  dependency-type: direct:production
  dependency-group: rs-dependencies
...

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

scripts/attestation_policy/Cargo.toml

@@ -9,5 +9,5 @@ edition = "2021"
 clap = { version = "4.0", features = ["derive"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-sev = "4.0.0"
+sev = "5.0.0"
 base64 = "0.22.1"