Update README.rst (#512)

README.rst

@@ -2,6 +2,12 @@
 Django Microsoft Authentication Backend
 =======================================
 
+Deprecated
+----------
+
+The point of this package was always to provide basic auth for the common Microsoft auth provider and Xbox Live auth. The common Microsoft auth provider has changed radically since I made this package and I really just do have any interest in updating it. If you want something that does Azure AD auth, go check out [django-auth-adfs](https://github.com/snok/django-auth-adfs).
+
+-----------
 
 .. image:: https://img.shields.io/pypi/v/django_microsoft_auth.svg
     :target: https://pypi.python.org/pypi/django_microsoft_auth