Update Rust crate rdkafka to 0.38.0

Author: renovate[bot]

Cargo.lock

@@ -22,7 +22,7 @@ clap-verbosity-flag = {version = "3.0.2", features = ["tracing"]}
 futures = "0.3.31"
 metrics = "0.24.1"
 metrics-exporter-prometheus = "0.17.0"
-rdkafka = "0.37.0"
+rdkafka = "0.38.0"
 risotto-lib = { path = "../risotto-lib", version = "0.4.0" }
 serde = { version = "1.0.217", features = ["derive"] }
 tokio = { version = "1.42.0", features = ["full"] }