MINOR: Add line-continuation to shell command (#204)

Co-authored-by: dengziming <dengziming@growingio.com>

README.md

@@ -33,9 +33,9 @@ The official Docker image for Kafka UI is hosted here: [hub.docker.com/r/provect
 Launch Docker container in the background:
 ```sh
 
-docker run -p 8080:8080
-	-e KAFKA_CLUSTERS_0_NAME=local
-	-e KAFKA_CLUSTERS_0_BOOTSTRAPSERVERS=kafka:9092
+docker run -p 8080:8080 \
+	-e KAFKA_CLUSTERS_0_NAME=local \
+	-e KAFKA_CLUSTERS_0_BOOTSTRAPSERVERS=kafka:9092 \
 	-d provectuslabs/kafka-ui:latest 
 
 ```