[ussuri][goal] Drop python 2.7 support and testing

OpenStack is dropping the py2.7 support in ussuri cycle.

Congress-dashboard is ready with python 3 and ok to drop the
python 2.7 support.

Complete discussion & schedule can be found in
- http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Depends-On: https://review.opendev.org/#/c/693631/
Change-Id: I433d289bb0a6d1c8bea5492b2fefa2e000636294

.zuul.yaml

@@ -3,7 +3,6 @@
       - check-requirements
       - horizon-non-primary-django-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3

doc/requirements.txt

@@ -1,4 +1,3 @@
-sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
 sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4' # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0
 reno>=2.5.0 # Apache-2.0

releasenotes/notes/drop-py-2-7-0b1f5e1450e2991c.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of Congress-dashboard
+    to support python 2.7 is OpenStack Train. The minimum version of Python now
+    supported by Congress-dashboard is Python 3.6.

requirements.txt

@@ -8,8 +8,7 @@
 #
 # PBR should always appear first
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
-Django<2,>=1.11;python_version<'3.0' # BSD
-Django<2.1,>=1.11;python_version>='3.0' # BSD
+Django>=1.11;python_version>='3.0' # BSD
 django-babel>=0.6.2 # BSD
 django-compressor>=2.0 # MIT
 keystoneauth1>=3.4.0 # Apache-2.0

setup.cfg

@@ -13,8 +13,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py37,py36,py27,py3-{dj111,dj22},pep8
+envlist = py37,py36,py3-{dj111,dj22},pep8
 minversion = 2.0
 skipsdist = True