CI: Java Version

[missinglink]

From the Travis logs while testing elasticsearch@7 support:

future versions of Elasticsearch will require Java 11; your Java version from [/usr/lib/jvm/java-8-oracle/jre] does not meet this requirement

[orangejulius]

Huh weird. My understanding was that ES7 bundles Java to avoid all this pain.

[missinglink]

this config is a useful reference: https://github.com/taskrabbit/elasticsearch-dump/blob/master/.travis.yml

[missinglink]

it could be that we are explicitly overriding the default version in our CI config?