Fix flake8 issues since release 3.6.0
Flake8 had a new release which raise new issues, namely:
W504: line break after binary operator
F841: local variable 'ex' is assigned to but never used
W605: invalid escape sequence
F821: undefined name 'buffer' (noqa seems the only way to avoid this false positive)
Also pin flake8>=3.6 in our tests and make explicit that we use python3 to run
flake8 tests.
.. _profile_module:
:mod:`cubicweb.pyramid.profile`
===============================
.. automodule:: cubicweb.pyramid.profile
Views
-----
.. autofunction:: ping
.. autofunction:: cnx
WSGI
----
.. autofunction:: wsgi_profile