docs: update limitations about json query support and django version …

…support. (#729)

* refactor: update asset image files with latest changes

* docs: update limitations about json query support

* docs: update readme with supported django versions detail

* docs: update django project url in readme

README.rst

@@ -80,14 +80,13 @@ Windows
 Supported versions
 ~~~~~~~~~~~~~~~~~~
 
-At the moment, this library only supports `Django 2.2
-<https://docs.djangoproject.com/en/2.2/>`__. It also requires Python version
-3.6 or later.
-
-This package follows a common versioning convention for Django plugins: the
-major and minor version components of this package should match the installed
-version of Django. That is, ``django-google-spanner~=2.2`` works with
-``Django~=2.2``.
+The library supports `Django 2.2
+<https://docs.djangoproject.com/en/2.2/>`_, and `Django 3.2
+<https://docs.djangoproject.com/en/3.2/>`_.
+Both versions are long-term support (LTS) releases for the
+`Django project<https://www.djangoproject.com/download/#supported-versions>_`.
+The minimum required Python version is 3.6.
+
 
 Installing the package
 ~~~~~~~~~~~~~~~~~~~~~~

docs/limitations.rst

@@ -158,8 +158,9 @@ Example:
 
 More details about this issue can be tracked `here <https://code.djangoproject.com/ticket/33052>`_. 
 
-Support for Json field is currently not there
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-This library currently does not support json. For more info on json support support follow this `github issue <https://github.com/googleapis/python-spanner-django/issues/707>`_.
+Support for query inside JSONfield is currently not there
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+We have also added support for JSON object storage and retrieval with Django 3.2.x support in v2.2.1b4 release,
+but querying inside the JSONfield is not supported in the current `django-google-spanner` release.
+This feature is being worked on and can be tracked `here <https://github.com/googleapis/python-spanner-django/issues/716>`_.