[py2removal] pyflakes -> pyflakes3
While the actual tests appear to use pyflakes3, the build and test depends still reference the (python 2) pyflakes package (which recommends the python3 version). This drops any reference to the python2 version.
While the actual tests appear to use pyflakes3, the build and test depends still reference the (python 2) pyflakes package (which recommends the python3 version). This drops any reference to the python2 version.