Coming from https://github.com/opensearch-project/opensearch-plugins/issues/64, default CI Java version to 11 (LTS), and run tests on 8, 14 and 17. - [ ] Change the default Java version for CI in GitHub actions from 14/15 to 11 (LTS). - [ ] Add Java 8, 14 (used before), and 17 (next LTS) to the CI matrix. - [ ] Document Java versions in DEVELOPER_GUIDE.md.
Coming from opensearch-project/opensearch-plugins#64, default CI Java version to 11 (LTS), and run tests on 8, 14 and 17.