Fixed rdkafka example

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

Author: slinkydeveloper

cloudevents-sdk-rdkafka/Cargo.toml

@@ -18,9 +18,9 @@ cloudevents-sdk = { version = "0.2.0", path = ".." }
 lazy_static = "1.4.0"
 rdkafka = { version = "^0.24", default-features = false }
 
-
 [dev-dependencies]
 url = { version = "^2.1" }
 serde_json = "^1.0"
 chrono = { version = "^0.4", features = ["serde"] }
 futures = "0.3.5"
+rdkafka = { version = "^0.24" }