Updated admin's jQuery to 2.2.3.

Django admin JavaScript makes use of the `jQuery`_ library.

To avoid conflicts with user-supplied scripts or libraries, Django's jQuery

(version 2.1.4) is namespaced as ``django.jQuery``. If you want to use jQuery

(version 2.2.3) is namespaced as ``django.jQuery``. If you want to use jQuery

in your own admin JavaScript without including a second copy, you can use the

``django.jQuery`` object on changelist and add/edit views.

.. versionchanged:: 1.9

    The embedded jQuery has been upgraded from 1.11.2 to 2.1.4. This drops

    The embedded jQuery was upgraded from 1.11.2 to 2.1.4. This drops

    support for Internet Explorer 8 and below. You can restore support by

    :ref:`including your own version of jQuery 1.X <admin-browser-support-19>`.

.. versionchanged:: 1.10

    The embedded jQuery was upgraded from 2.1.4 to 2.2.3.

The :class:`ModelAdmin` class requires jQuery by default, so there is no need

to add jQuery to your ``ModelAdmin``’s list of media resources unless you have

a specific need. For example, if you require the jQuery library to be in the

* Added "No date" and "Has date" choices for ``DateFieldListFilter`` if the

  field is nullable.

* The jQuery library embedded in the admin is upgraded from version 2.1.4 to

  2.2.3.

:mod:`django.contrib.admindocs`

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