Bump serde_with from 3.8.1 to 3.9.0 in /protocol

Bumps [serde_with](https://github.com/jonasbb/serde_with) from 3.8.1 to 3.9.0.
- [Release notes](https://github.com/jonasbb/serde_with/releases)
- [Commits](jonasbb/serde_with@v3.8.1...v3.9.0)

---
updated-dependencies:
- dependency-name: serde_with
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

protocol/Cargo.toml

@@ -10,6 +10,6 @@ chrono = { version = "0.4", features = ["serde"] }
 uuid = { version = "1.8.0", features = ["v4", "serde"] }
 sqlx = { version = "0.7", features = ["macros", "chrono", "uuid"] }
 serde = "1.0"
-serde_with = { version = "3.7", features = ["chrono_0_4"] }
+serde_with = { version = "3.9", features = ["chrono_0_4"] }
 derive_more = "0.99"