Release Checklist
-----------------------------------------
[ ] Update classifiers in setup.cfg to include the latest supported Python
    versions.
[ ] Update the metadata in zonefile_metadata.json to include the latest tzdata
    release from https://www.iana.org/time-zones.
[ ] If necessary, update the tzdata mirror at https://github.com/dateutil/tzdata
[ ] Update NEWS with list of changes:
    [ ] Invoke `tox -e towncrier -- --version <NEXT_VERSION>`
    [ ] Make sure that only `template.rst` remains in changelog.d/
    [ ] Manually clean up the new NEWS file.
    [ ] Replace entries in the "Misc" section that are not likely to be
        interesting to anyone consuming the package (e.g. changes to CI) with
        a reference to the Github PR.
[ ] Commit the changes in git and make a pull request.
[ ] Accept the pull request and tag the repository with the release number.
[ ] Add the contents of the NEWS file to the Github release notes for the
    release.
[ ] Upload the source and binary distributions with `tox -e release`.

Optional:
----------
[ ] Check that README.rst is up-to-date.
[ ] Check that the documentation builds correctly (cd docs, make html)


Instructions
-----------------------------------------
See the instructions at https://packaging.python.org/en/latest/distributing/
for more details.


Versioning
----------
Try and keep to a semantic versioning scheme (http://semver.org/). The versions
are managed with `setuptools_scm`, so to update the version, simply tag the
relevant commit with the new version number.


Building and Releasing
----------------------
Building and releasing can be done using the `release.py` script, which
automates building, signing and uploading. Since it uses GPG for signing and
for decrypting a stored token, it requires that `gpg` be installed on your
system. Because it has python dependencies, the best way to use the
`release.py` script is to invoke it using `tox`. To build the source and binary
distributions, use:

    tox -e build

This will build the distributions in `dist/`. Once that is done, you can release
them with:

    tox -e release

if you have the token stored in your `~/.pypirc` file. If you have stored the
relevant token in an encrypted file, use the `--passfile` argument:

    tox -e release -- --passfile .token.gpg

The `release` command defaults to uploading to test.pypi.org. To upload to
pypi.org, use the `--release` flag, so putting it all together, we have:

    tox -e build
    tox -e release -- --passfile .token.gpg --release