hacking 6.0.0 release contains flake8 5.0.4, which started to show the
following error:
./openstack_releases/versionutils.py:54:14: E275 missing whitespace after keyword
yield('Version %s looks like a pre-release and the release '
This patch adds a whitespace after the 'yield' keyword to make the pep8
job pass.
Change-Id: I433ccb6a31cc450a666673374b78dcc1fea1bb7b