Switch to new Framework :: Zope :: 3 classifier

See zopefoundation/z3c.authviewlet#6 (comment)
for the background behind this.

setup.py

@@ -70,7 +70,7 @@ def test_suite():
           'Programming Language :: Python :: Implementation :: PyPy',
           'Operating System :: OS Independent',
           'Topic :: Internet :: WWW/HTTP',
-          'Framework :: Zope3',
+          'Framework :: Zope :: 3',
       ],
       description='Browser resources implementation for Zope.',
       long_description=long_description,