Switch to hacking 3.0

This patch update hacking version to 3.0.0[1]. In order to make code compatible
with new hacking rules line break before/after binary operator I have added
W504 into ignore list in tox.ini. It also drop flake8, hacking, django-babel,
and mox3 packages from lower-requirements.txt.

[1] http://lists.openstack.org/pipermail/openstack-discuss/2020-May/014828.html

Change-Id: I96fc5ca23010958d68cf261793489580b57f3a4f

lower-constraints.txt

@@ -14,7 +14,6 @@ decorator==3.4.0
 deprecation==1.0
 Django==2.2
 django-appconf==1.0.2
-django-babel==0.5.1
 django-compressor==2.0
 django-pyscss==2.0.2
 dogpile.cache==0.6.2
@@ -22,10 +21,8 @@ eventlet==0.18.2
 extras==1.0.0
 fasteners==0.7.0
 fixtures==3.0.0
-flake8==2.5.5
 futurist==1.2.0
 greenlet==0.4.10
-hacking==0.12.0
 horizon==17.1.0
 idna==2.6
 iso8601==0.1.11
@@ -41,7 +38,6 @@ MarkupSafe==1.0
 mccabe==0.2.1
 mock==2.0.0
 monotonic==0.6
-mox3==0.20.0
 msgpack-python==0.4.0
 munch==2.1.0
 netaddr==0.7.18

test-requirements.txt

@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+hacking>=3.0.1,<3.1.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 selenium>=2.50.1 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0

tox.ini

@@ -80,9 +80,10 @@ commands = npm install
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.
 # F405 TEMPLATES may be undefined, or defined from star imports
+# W504 line break after binary operator
 # (because it is not easy to avoid this in openstack_dashboard.test.settings)
 show-source = True
-ignore = E123,E125,F405
+ignore = E123,E125,F405,W504
 builtins = _
 exclude=.venv,.git,.tox,.tmp,dist,doc,*lib/python*,*egg,build,node_modules