We do not have packaged furo and it is not needed to run tests.

--- zope_interface-8.0.1/setup.py.orig
+++ zope_interface-8.0.1/setup.py
@@ -140,7 +140,7 @@
     extras_require={
         'docs': ['Sphinx',
                  'repoze.sphinx.autointerface',
-                 'furo'],
+                 ],
         'test': tests_require,
         'testing': testing_extras,
     },