TLS certificate management has been split off into the django-simple-certmanager_
library, which is now a dependency of this project. You should update the following
references in your own code:

* ``zgw_consumers.constants.CertificateTypes`` -> ``simple_certmanager.constants.CertificateTypes``
* ``zgw_consumers.models.Certificate`` -> ``simple_certmanager.models.Certificate``

The ``Certificate`` model is identical to the one shipped in zgw-consumers before
0.21.0. As a convenience, ``zgw_consumers.Certifcate`` is still provided, which is a
proxy model to ``simple_certmanager.Certificate``.

**Other changes**

* Dropped support for Django 2.2. Only Django 3.2 and upwards are supported.
* The minimum version of gemma-zds-client_ has been bumped to the 1.0.x series

.. _django-simple-certmanager: https://pypi.org/project/django-simple-certmanager/
.. _gemma-zds-client: https://pypi.org/project/gemma-zds-client/