Unsupported config option for prosoul: 'depends_on'

version: '2'

services:
    elasticsearch:
      image: bitergia/elasticsearch:6.1.0
      command: /elasticsearch/bin/elasticsearch -E network.bind_host=0.0.0.0
      ports:
        - "9200:9200"
      environment:
        - ES_JAVA_OPTS=-Xms2g -Xmx2g

    kibiter:
      image: bitergia/kibiter:6.1.0-optimized
      links:
        - elasticsearch
      ports:
       - "5601:5601"

    prosoul:
      image: bitergia/prosoul
      ports:
       - "8000:8000"
      depends_on:
       - kibiter
       - elasticsearch
      environment:
       - ALLOWED_HOSTS=prosoul localhost 127.0.0.1
       - ES_URL=https://admin:admin@elasticsearch:9200
       - KIBITER_URL=https://kibiter:80