Update confluentinc/cp-kafka-rest Docker tag to v7.9.4

Author: renovate[bot]

components/cluster/kafka/docker-compose.yml

@@ -127,7 +127,7 @@ services:
       - kafka-schema-registry
 
   kafka-rest-proxy:
-    image: confluentinc/cp-kafka-rest:7.8.1
+    image: confluentinc/cp-kafka-rest:7.9.4
     hostname: kafka-rest-proxy
     ports:
       - "8082:8082"