List of steps to reproduce (step by step, including full links if applicable):
https://ci.appveyor.com/project/Ladsgroup/pywikibot-g4xqx/builds/41145028/job/k8mp8y9e0ij226lp
What happens?:
cffi module was updated on 13th october[1] and does not longer support Python 3.5 but is still installed for that version.
Collecting cffi>=1.0.0 (from brotlipy->httpbin->pytest-httpbin->-r dev-requirements.txt (line 14)) 161 Downloading https://files.pythonhosted.org/packages/00/9e/92de7e1217ccc3d5f352ba21e52398372525765b2e0c4530e6eb2ba9282a/cffi-1.15.0.tar.gz (484kB)