chore(deps): update apache-avro requirement in /relay

Updates the requirements on [apache-avro](https://github.com/apache/avro-rs) to permit the latest version.
- [Release notes](https://github.com/apache/avro-rs/releases)
- [Changelog](https://github.com/apache/avro-rs/blob/main/CHANGELOG.md)
- [Commits](apache/avro-rs@rel/release-0.18.0-RC1...rel/release-0.20.0)

---
updated-dependencies:
- dependency-name: apache-avro
  dependency-version: 0.20.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

relay/Cargo.toml

@@ -41,7 +41,7 @@ lapin = "2.5.0"
 strum = { version = "0.27.1", features = ["derive"] }
 thiserror = "2.0.12"
 backoff = { version = "0.4.0", features = ["tokio"] }
-apache-avro = { version = "0.17.0", features = ["derive"] }
+apache-avro = { version = "0.20.0", features = ["derive"] }
 lazy_static = "1.5.0"
 
 [dev-dependencies]