title: filebeat is not creating index with my name
body: <p>I am using filebeat to send my application logs to Elasticsearch and directly connecting to my Elasticsearch for sending the logs.</p>
  
  <p><strong>My file beat configuration</strong></p>
  
  <pre><code>filebeat.config:
    modules:
      path: ${path.config}/modules.d/*.yml
      reload.enabled: false
  
  filebeat.inputs:
    - type: log
      paths:
        - "/var/log/*.log"
  setup.ilm.enabled: false
  setup.template.overwrite: true
  output.elasticsearch:
    hosts: ["aws-es:443"]
    output.elasticsearch.index: "myapp-%{[agent.version]}-%{+yyyy.MM.dd}"
    username: '${ELASTICSEARCH_USERNAME:}'
    password: '${ELASTICSEARCH_PASSWORD:}
  </code></pre>
  
  <p>Please note that in <code>output.elasticsearch.index:</code> I am giving myapp as prefix to my index name in Elasticsearch but filebeat is creating index with <code>filebeat-7.7.0-2020.05.31</code> name ie using its own name <code>filebeat</code> as prefix which I don't want as I am having multiple applications and want to create a separate index for them.</p>