Update recommended Python version to 3.6
On the topic of which points this out for the Windows beets.reg extra.
@@ -82,7 +82,7 @@ into this if you've installed Python yourself with `Homebrew`_ or otherwise.)
If this happens, you can install beets for the current user only (sans
``sudo``) by typing ``pip install --user beets``. If you do that, you might want
-to add ``~/Library/Python/2.7/bin`` to your ``$PATH``.
+to add ``~/Library/Python/3.6/bin`` to your ``$PATH``.
.. _System Integrity Protection: https://support.apple.com/en-us/HT204899
.. _Homebrew: http://brew.sh
@@ -93,7 +93,7 @@ Installing on Windows
Installing beets on Windows can be tricky. Following these steps might help you
get it right:
-1. If you don't have it, `install Python`_ (you want Python 2.7).
+1. If you don't have it, `install Python`_ (you want Python 3.6).
2. If you haven't done so already, set your ``PATH`` environment variable to
include Python and its scripts. To do so, you have to get the "Properties"
