fix setuptools entry_point link

Author: imba-tjd

source/overview.rst

@@ -167,7 +167,7 @@ Python's native packaging is mostly built for distributing reusable
 code, called libraries, between developers. You can piggyback
 **tools**, or basic applications for developers, on top of Python's
 library packaging, using technologies like `setuptools entry_points
-<http://setuptools.readthedocs.io/en/latest/setuptools.html#automatic-script-creation>`_.
+<https://setuptools.readthedocs.io/en/latest/userguide/entry_point.html>`_.
 
 Libraries are building blocks, not complete applications. For
 distributing applications, there's a whole new world of technologies