Drop python 2.7 support and testing

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

Remove explicit listed jobs from check queue, they are in the templates.

- Update jobs
- Remove python 2.7 stanza from setup.py
- Add requires on python >= 3.6 to setup.cfg so that pypi and pip
  know about the requirement
- Remove obsolete sections from setup.cfg:
  * Wheel is not needed for python 3 only repo
  * Some other sections are obsolete
- Update classifiers
- Update requirements, no need for python_version anymore

Co-Authored-By: Andreas Jaeger <aj@suse.com>
Change-Id: I4a1976c78b0fe69cc1b423c516d557838cb6d59b

doc/requirements.txt

@@ -1,5 +1,4 @@
 # Even if we do not build doc with python 2, we have to
 # push that content due to some global check.
-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
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2  # BSD
 openstackdocstheme>=1.20.0 # Apache-2.0

releasenotes/notes/drop-python-2-7-73d3113c69d724d6.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. The minimum version of Python now
+    supported by paunch is Python 3.6.

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/paunch/latest/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,8 +14,8 @@ 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 :: Implementation :: CPython
+    Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
@@ -34,14 +35,6 @@ paunch =
     list = paunch.cmd:List
     debug = paunch.cmd:Debug
 
-[build_sphinx]
-source-dir = doc/source
-build-dir = doc/build
-all_files = 1
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
 [compile_catalog]
 directory = paunch/locale
 domain = paunch
@@ -55,11 +48,3 @@ input_file = paunch/locale/paunch.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = paunch/locale/paunch.pot
-
-[build_releasenotes]
-all_files = 1
-build-dir = releasenotes/build
-source-dir = releasenotes/source
-
-[wheel]
-universal = 1

setup.py

@@ -13,17 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
-
 setuptools.setup(
     setup_requires=['pbr>=1.8'],
     pbr=True)

tox.ini

@@ -1,7 +1,8 @@
 [tox]
-minversion = 2.0
+minversion = 3.1.1
 envlist = pep8,py37
 skipsdist = False
+ignore_basepython_conflict = True
 
 [testenv]
 basepython = python3
@@ -38,7 +39,8 @@ commands =
 [testenv:docs]
 deps = -r{toxinidir}/doc/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = python setup.py build_sphinx
+commands =
+  sphinx-build -a -E -W -d doc/build/doctrees -b html doc/source doc/build/html
 
 [testenv:releasenotes]
 deps = -r{toxinidir}/doc/requirements.txt

zuul.d/layout.yaml

@@ -1,15 +1,11 @@
 - project:
     templates:
-      - openstack-python3-ussuri-jobs
       - check-requirements
+      - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
-      - openstack-python-jobs
       - release-notes-jobs-python3
     check:
       jobs:
-        - openstack-tox-pep8
-        - openstack-tox-py36
-        - openstack-tox-py37
         - tripleo-ci-centos-8-scenario004-standalone:
             dependencies:
               - openstack-tox-pep8