[elasticsearch]: 5.6 compability

[viceice]

• Chart version not bumped (the versions are all bumped and released at the same time)
• README.md updated with any new values or changes
• Updated template tests in ${CHART}/tests/*.py
• Updated integration tests in ${CHART}/examples/*/test/goss.yaml

remote_cluster_client is not available on es 5.6

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service]

❌ Author of the following commits did not sign a Contributor Agreement:
e97e999

Please, read and sign the above mentioned agreement if you want to contribute to this project

[viceice]

regression of #854

[jmlrt]

Hi @viceice,
Elasticsearch 5.6 isn't supported by these charts.

As mentionned in https://github.com/elastic/helm-charts/blob/master/README.md#support-matrix, only 6.8.x and 7.x.x versions are supporting using the same version for Helm charts (https://github.com/elastic/helm-charts/releases) and for Elasticsearch.

For this reason, I'll close your PR and I would highly encourage you to plan an upgrade to a supported Elasticsearch version.

Don't hesitate to comment back if you have any question.

[viceice]

OK, I fould a workaround for now: simply using the v6.8.13 or the chart. That works with official es 5.6 docker images 😏

Yes, i plan to upgrade to a newer es version, but I'm currently blocked by Multiple mapping types are not supported in indices created in 6.0.
That needs a hurge app refactoring, so deferred 🙃