Update README with version support

Author: pelme

README.rst

@@ -15,7 +15,7 @@ pytest-django allows you to test your Django project/applications with the
   <http://pytest-django.readthedocs.org/en/latest/contributing.html>`_
 * Version compatibility:
 
-  * Django: 1.3-1.8 and latest master branch (compatible at the time of each release)
+  * Django: 1.4-1.8 and latest master branch (compatible at the time of each release)
   * Python: CPython 2.6-2.7,3.2-3.4 or PyPy 2,3
   * pytest: 2.6.x