Update towncrier to 21.9.0

[pyup-bot]

This PR updates towncrier from 19.2.0 to 21.9.0.

Changelog

21.3.0

=============================

No significant changes since the previous release candidate.

21.3.0.rc1

=================================

Features
--------

- Ticket number from file names will be stripped down to avoid ticket links such as ``007``. (`126 <https://github.com/hawkowl/towncrier/issues/126>`_)
- Allow definition of the project ``version`` and ``name`` in the configuration file.
This allows use of towncrier seamlessly with non-Python projects. (`165 <https://github.com/hawkowl/towncrier/issues/165>`_)
- Improve news fragment file name parsing to allow using file names like
``123.feature.1.ext`` which are convenient when one wants to use an appropriate
extension (e.g. ``rst``, ``md``) to enable syntax highlighting. (`173 <https://github.com/hawkowl/towncrier/issues/173>`_)
- The new ``--edit`` option of the ``create`` subcommand launches an editor for entering the contents of the newsfragment. (`275 <https://github.com/hawkowl/towncrier/issues/275>`_)
- CPython 3.8 and 3.9 are now part of our automated test matrix and are officially supported. (`291 <https://github.com/hawkowl/towncrier/issues/291>`_)
- When searching for the project, first check for an existing importable instance.
This helps if the version is only available in the installed version and not the source. (`297 <https://github.com/hawkowl/towncrier/issues/297>`_)
- Support building with PEP 517. (`314 <https://github.com/hawkowl/towncrier/issues/314>`_)


Bugfixes
--------

- Configuration errors found during command line execution now trigger a message to stderr and no longer show a traceback. (`84 <https://github.com/hawkowl/towncrier/issues/84>`_)
- A configuration error is triggered when the newsfragment files couldn't be discovered. (`85 <https://github.com/hawkowl/towncrier/issues/85>`_)
- Invoking towncrier as `python -m towncrier` works. (`163 <https://github.com/hawkowl/towncrier/issues/163>`_)
- ``check`` subcommand defaults to UTF-8 encoding when ``sys.stdout.encoding`` is ``None``.
This happens, for example, with Python 2 on GitHub Actions or when the output is piped. (`175 <https://github.com/hawkowl/towncrier/issues/175>`_)
- Specifying ``title_format`` disables default top line creation to avoid duplication. (`180 <https://github.com/hawkowl/towncrier/issues/180>`_)


Improved Documentation
----------------------

- The README now mentions the possibility to name the configuration file
``towncrier.toml`` (in addition to ``pyproject.toml``). (`172 <https://github.com/hawkowl/towncrier/issues/172>`_)
- ``start_line`` corrected to ``start_string`` in the readme to match the long standing implementation. (`277 <https://github.com/hawkowl/towncrier/issues/277>`_)

19.9.0

=============================

No significant changes.

19.9.0rc1

================================

Features
--------

- Add ``create`` subcommand, which can be used to quickly create a news
fragment command in the location defined by config. (`4 <https://github.com/hawkowl/towncrier/issues/4>`_)
- Add support for subcommands, meaning the functionality of the ``towncrier``
executable is now replaced by the ``build`` subcommand::

   $ towncrier build --draft

A new ``check`` subcommand is exposed. This is an alternative to calling the
``towncrier.check`` module manually::

   $ towncrier check

Calling ``towncrier`` without a subcommand will result in a call to the
``build`` subcommand to ensure backwards compatibility. This may be removed in a
future release. (`144 <https://github.com/hawkowl/towncrier/issues/144>`_)
- Towncrier's templating now allows configuration of the version header. *CUSTOM TEMPLATE USERS PLEASE NOTE: You will need to add the version header information to your template!* (`147 <https://github.com/hawkowl/towncrier/issues/147>`_)
- towncrier now accepts the --config argument to specify a custom configuration file (`157 <https://github.com/hawkowl/towncrier/issues/157>`_)
- There is now the option for ``all_bullets = false`` in the configuration.
Setting ``all_bullets`` to false means that news fragments have to include
the bullet point if they should be rendered as enumerations, otherwise
they are rendered directly (this means fragments can include a header.).
It is necessary to set this option to avoid (incorrect) automatic indentation
of multiline fragments that do not include bullet points.
The ``single-file-no-bullets.rst`` template gives an example of
using these options. (`158 <https://github.com/hawkowl/towncrier/issues/158>`_)
- The ``single_file`` option can now be added to the configuration file. When set to ``true``, the filename key can now be formattable with the ``name``, ``version``, and ``project_date`` format variables. This allows subsequent versions to be written out to new files instead of appended to an existing one. (`161 <https://github.com/hawkowl/towncrier/issues/161>`_)
- You can now specify Towncrier-bundled templates in your configuration file. Available templates are `default`, `hr-between-versions` (as used in attrs), and `single-file-no-bullets`. (`162 <https://github.com/hawkowl/towncrier/issues/162>`_)


Bugfixes
--------

- Accept newsfragment filenames with multiple dots, like `fix-1.2.3.bugfix`. (`142 <https://github.com/hawkowl/towncrier/issues/142>`_)


Deprecations and Removals
-------------------------

- The `--pyproject` option for `towncrier check` is now replaced with `--config`, for consistency with other commands. (`162 <https://github.com/hawkowl/towncrier/issues/162>`_)

Links

• PyPI: https://pypi.org/project/towncrier
• Changelog: https://pyup.io/changelogs/towncrier/
• Repo: https://github.com/hawkowl/towncrier