Features
* A new `deploy` command supports uploading data files to S3, allowing the
complete pathogen build lifecycle to happen using this package.
* The `check-setup` and `update` commands now check if the CLI itself is out of
date and could be updated.
Documentation
* Brief descriptions of the changes in each release are now kept in the
`CHANGES.md` file. You're reading it!
Development
* Describe basic development practices for this package in the README.
* Commit to [semantic versioning](https://semver.org), which I'd been
neglecting previously when bumping versions.
* Static type checking is now supported for a small fraction of the source code
and runs clean under mypy. This is included in Travis CI testing. The goal
is to add more type annotations going forward.