Fix deprecated-urllib-function

Add dependency on six.

CHANGES.rst

@@ -4,7 +4,8 @@ Alterações
 2.0.3 (unreleased)
 ^^^^^^^^^^^^^^^^^^
 
-- Nothing changed yet.
+- Adiciona dependência no `six <https://pypi.org/project/six/>`_ para futura compatibilidade com Python 3.
+  [hvelarde]
 
 
 2.0.2 (2017-12-22)

setup.py

@@ -46,6 +46,7 @@
           'raptus.autocompletewidget',
           'rdflib',
           'setuptools',
+          'six',
           'zope.component',
           'z3c.form',
           'zope.interface',

src/brasil/gov/vcge/browser/viewlets.py

@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 """Modulo que implementa o(s) viewlet(s) do VCGE."""
+from six.moves.urllib.parse import urlencode  # noqa: I001
 from Acquisition import aq_base
 from Acquisition import aq_inner
 from plone.app.layout.viewlets import ViewletBase
 from Products.CMFPlone.utils import safe_hasattr
 from Products.Five.browser.pagetemplatefile import ViewPageTemplateFile
-from urllib import urlencode
 from zope.component import queryUtility
 from zope.schema.interfaces import IVocabularyFactory