Update wtforms to 2.3.0

[pyup-bot]

This PR updates WTForms from 2.1 to 2.3.0.

Changelog

2.2.1

-------------

Released on June 7th, 2018

-   :class:`~fields.StringField` only sets ``data = ''`` when form data
 is empty and an initial value was not provided. This fixes an issue
 where the default value wasn't rendered with the initial form.
 (:issue:`291`, :issue:`401`)

2.2

-----------

Released on June 2nd, 2018

-   Merged new and updated translations from the community.
-   Passing ``data_`` args to render a field converts all the
 underscores to hyphens when rendering the HTML attribute, not just
 the first one. ``data_foo_bar`` becomes ``data-foo-bar``. (:pr:`248`)
-   The :class:`~validators.UUID` validator uses the :class:`uuid.UUID`
 class instead of a regex. (:pr:`251`)
-   :class:`~fields.SelectField` copies the list of ``choices`` passed
 to it so modifying an instance's choices will not modify the global
 form definition. (:pr:`286`)
-   Fields call :meth:`~fields.Field.process_formdata` even if the raw
 data is empty. (:pr:`280`)
-   Added a :class:`~fields.MultipleFileField` to handle a multi-file
 input. :class:`~fields.FileField` continues to handle only one
 value. The underlying :class:`~widgets.FileInput` widget gained a
 ``multiple`` argument. (:pr:`281`)
-   :class:`~fields.SelectField` choices can contain HTML (MarkupSafe
 ``Markup`` object or equivalent API) and will be rendered properly.
 (:pr:`302`)
-   :class:`~fields.TimeField` and
 :class:`html5.TimeField <fields.html5.TimeField>` were added.
 (:pr:`254`)
-   Improved :class:`~validators.Email`. Note that it is still
 unreasonable to validate all emails with a regex and you should
 prefer validating by actually sending an email. (:pr:`294`)
-   Widgets render the ``required`` attribute when using a validator
 that provides the ``'required'`` flag, such as
 :class:`~validators.DataRequired`. (:pr:`361`)
-   Fix a compatibility issue with SQLAlchemy 2.1 that caused
 :class:`~ext.sqlalchemy.fields.QuerySelectField` to fail with
 ``ValueError: too many values to unpack``. (:pr:`391`)

Links

• PyPI: https://pypi.org/project/wtforms
• Changelog: https://pyup.io/changelogs/wtforms/
• Docs: https://wtforms.readthedocs.io/

[pyup-bot]

Closing this in favor of #67