[Backend Dependencies Update] Update werkzeug to 0.16.1

[pyup-bot]

This PR updates werkzeug from 0.15.6 to 0.16.1.

Changelog

0.16.1

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

Released 2020-01-27

-   Fix import location in deprecation messages for subpackages.
 :issue:`1663`
-   Fix an SSL error on Python 3.5 when the dev server responds with no
 content. :issue:`1659`

0.16.0

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

Released 2019-09-19

-   Deprecate most top-level attributes provided by the ``werkzeug``
 module in favor of direct imports. The deprecated imports will be
 removed in version 1.0.

 For example, instead of ``import werkzeug; werkzeug.url_quote``, do
 ``from werkzeug.urls import url_quote``. A deprecation warning will
 show the correct import to use. ``werkzeug.exceptions`` and
 ``werkzeug.routing`` should also be imported instead of accessed,
 but for technical reasons can't show a warning.

 :issue:`2`, :pr:`1640`

Links

• PyPI: https://pypi.org/project/werkzeug
• Changelog: https://pyup.io/changelogs/werkzeug/
• Homepage: https://palletsprojects.com/p/werkzeug/

[pyup-bot]

Closing this in favor of #800