graphite reporting not working on docker image 0.6.6

[yehonatanz]

Describe the bug
Version 0.6.6 from dockerhub not reporting to graphite when configured. Version 0.6.5 works perfectly with same config.

To Reproduce
zip with docker-compose.yml and application.conf: kle.zip

docker-compose.yml:

version: '3.8'

services:
  zookeeper:
    image: 'docker.io/bitnami/zookeeper:3-debian-10'
    ports:
      - '2181:2181'
    environment:
      - ALLOW_ANONYMOUS_LOGIN=yes
  kafka:
    image: 'docker.io/bitnami/kafka:2-debian-10'
    ports:
      - '9092:9092'
    environment:
      - KAFKA_CFG_ZOOKEEPER_CONNECT=zookeeper:2181
      - ALLOW_PLAINTEXT_LISTENER=yes
    depends_on:
      - zookeeper
  kafka-lag-exporter:
    image: lightbend/kafka-lag-exporter:0.6.6
    command: "bin/kafka-lag-exporter -Dconfig.file=/opt/docker/conf/application.conf"
    volumes:
      - './:/opt/docker/conf/' 
    depends_on:
      - kafka
      - graphite
  graphite:
    image: graphiteapp/graphite-statsd
    ports:
      - '8080:80'

application.conf:

kafka-lag-exporter {
  reporters.graphite.host = "graphite"
  reporters.graphite.port = 2003

  clusters = [
    {
      name = "my_kafka_cluster"
      bootstrap-brokers = "kafka:9092"
    }
  ]
}

Log:
kle.log
As you can see, prometheus is logged as a reporter but graphite isn't.

Environment

• Version 0.6.6
• Version of Apache Kafka cluster 2.7.0 (docker image bitnami/kafka:2.7.0-debian-10-r56)
• Run with Helm or Standalone: standalone docker image

Additional context
Version 0.6.5 work perfectly with same config at an identical environment.

[yehonatanz]

Found the cause.
It seems that since #157 it is required to specify:

sinks = ["GraphiteEndpointSink"]

in addtion to specifying graphite in reporters.

I'm OK with closing this issue, but I guess a README update is needed.