Update html5lib to 1.1

[pyup-bot]

This PR updates html5lib from 1.0.1 to 1.1.

Changelog

1.1

~~~

UNRELEASED

Breaking changes:

* Drop support for Python 3.3. (358)
* Drop support for Python 3.4. (421)

Deprecations:

* Deprecate the ``html5lib`` sanitizer (``html5lib.serialize(sanitize=True)`` and
``html5lib.filters.sanitizer``). We recommend users migrate to `Bleach
<https://github.com/mozilla/bleach>`. Please let us know if Bleach doesn't suffice for your
use. (443)

Other changes:

* Try to import from ``collections.abc`` to remove DeprecationWarning and ensure
``html5lib`` keeps working in future Python versions. (403)
* Drop optional ``datrie`` dependency. (442)

Links

• PyPI: https://pypi.org/project/html5lib
• Changelog: https://pyup.io/changelogs/html5lib/
• Repo: https://github.com/html5lib/html5lib-python