Pin hacking to < 4.0.1 to fix zuul gate issues. Test: Ran tox -e pep8 command to validate the flake8 job and result. Related-Bug: 1926172 Signed-off-by: Charles Short <charles.short@windriver.com> Change-Id: I74fec1c352b8947b58498e32b7554e54c77aaeaa