Bump flake8 version

Older flake8 versions are not compatible with Python 3.14.

"hacking", a package that contains flake8 plugins used by Openstack,
also needs to be updated.

test-requirements.txt

@@ -3,8 +3,10 @@
 # process, which may cause wedges in the gate later.
 
 setuptools>=65.0.0,<82  # pkg_resources removed in 82; required by sqlalchemy-migrate
-hacking>=6.0.1,<=6.0.1 # Apache-2.0
+hacking>=7.0.0,<7.1.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 ddt>=1.2.1 # MIT
 oslotest>=3.8.0 # Apache-2.0
 stestr>=4.2.1 # Apache-2.0
+flake8>=7.0.0
+pyflakes>=3.2.0