Maintain

Breaking

- Drop support for Python < 3.7.

- Changelog releaser now uses the unreleased name "TBD" instead of "Master".
`CHANGELOG.md` files must use "TBD" as the upcoming release name going
forward.

Enhancements

- Support using branches named `main` as a default branch (previously default
branches had to be named `master`).

- Repo commands now sort the list of repositories to provide a consistent
experience across macOS and Linux platforms.

Breaking

- Drop support for Python 3.3.

Enhancements

- Releasing no longer requires a git remote. Release can be used for local
repositories.
- Release now offers a `--verbose` flag to log what is happening during
release.
- GitHub releaser now allows you to upload artefacts to the GitHub release.
- GitHub releaser will now upload changelog release from `CHANGELOG.md` files.
- Hooks are now passed the VERSION as an environment variable.
- Hooks can now be placed in files inside `.maintain/hooks` such as
`.maintain/hooks/pre_release`.
- Changelog releaser allows you to specify custom sections.

yaml
release:
changelog:
sections:
'Breaking': major
'Enhancements': minor
'Bug Fixes': patch

- Configuration file can now be passed via the `--config` option.

Initial release.