**Announcement**
This is mostly a code cleanup (pylint/black/mypy formatting) release, but a few notable other changes were made to non-core code.
**Changes**
* Version bump `es_client==8.15.1`
* Updated `docker_test` contents to follow https://github.com/untergeek/es-docker-test-scripts
* Updated Dockerfile & `post4docker.py` to be more generic for easy sharing
* Updated Dockerfile to use more recent versions of Python and cx_Freeze
* Updated `pyproject.toml` to use new cx_Freeze methodology
* Updated dates in `LICENSE.txt`
* Updated `cli.py` to import `show_all_options` from `es_client`
* Updated `README.md` to correct several typos
* Removed `setup.py` as it was only for older cx_Freeze version
* Removed `src/es_fieldusage/helpers/` `client.py`, `logging.py` as `es_client` now provides them for us.
* Removed older files in `docker_test` that were superseded by the new version