druid/pull_request_template.md at 57765a499b4bc328a543c0988e0e2ce64b7834d5

Fixes #XXXX.

This PR has:

been self-reviewed.
- using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
added documentation for new or modified features or behaviors.
added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
added or updated version, license, or notice information in licenses.yaml
added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
added unit tests or modified existing tests to cover new code paths.
added integration tests.
been tested in a test Druid cluster.