Update ELK images
elasticsearch:
- https://github.com/docker-library/elasticsearch/commit/6f143ea: Update to 7.6.1
- https://github.com/docker-library/elasticsearch/commit/aafce2f: Update to 6.8.7
logstash:
- https://github.com/docker-library/logstash/commit/1bd7995: Update to 7.6.1
- https://github.com/docker-library/logstash/commit/16ffef2: Update to 6.8.7
kibana:
- https://github.com/docker-library/kibana/commit/c0ffb14: Update to 7.6.1
- https://github.com/docker-library/kibana/commit/3536799: Update to 6.8.7
Docker Library Bot