Update confluentinc/cp-kafka Docker tag to v8 (#616)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

docker-compose.yml

@@ -1,7 +1,7 @@
 services:
   kafka:
     container_name: kafka
-    image: confluentinc/cp-kafka:7.9.1
+    image: confluentinc/cp-kafka:8.0.0
 
     ports:
       - 9092:9092