Update sev requirement (#257)

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

Updates `sev` to 4.0.0
- [Commits](https://github.com/virtee/sev/compare/v3.1.1...v4.0.0)

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

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scripts/backend_info/Cargo.toml

@@ -9,4 +9,4 @@ edition = "2021"
 clap = { version = "4.0", features = ["derive"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-sev = "3.1.1"
+sev = "4.0.0"