[cleanup] Remove a check that can never be reached (#413)

The package metadata makes sure that the python version is at least
3.7. This package won't be installed for other python interpreters.

pylint_django/__init__.py

@@ -1,12 +1,7 @@
 """pylint_django module."""
-from __future__ import absolute_import
 
-import sys
 
 from pylint_django import plugin
 
-if sys.version_info < (3,):
-    raise DeprecationWarning("Version 0.11.1 was the last to support Python 2. Please migrate to Python 3!")
-
 register = plugin.register  # pylint: disable=invalid-name
 load_configuration = plugin.load_configuration  # pylint: disable=invalid-name