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

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

python-searchlightsclient 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

Change-Id: I37810f2e78523388a70cad0034f8d4d9e73e218b

.zuul.yaml

@@ -1,6 +1,5 @@
 - project:
     templates:
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - openstack-cover-jobs
       - publish-openstack-docs-pti

README.rst

@@ -148,6 +148,5 @@ Testing
 There are multiple test targets that can be run to validate the code.
 
 * tox -e pep8 - style guidelines enforcement
-* tox -e py27 - traditional unit testing with python 2.7
 * tox -e py36 - traditional unit testing with python 3.6
 * tox -e py37 - traditional unit testing with python 3.7

doc/requirements.txt

@@ -4,5 +4,4 @@
 
 openstackdocstheme>=1.30.0 # Apache-2.0
 sphinxcontrib-svg2pdfconverter>=0.1.0 # BSD
-sphinx>=1.8.0,<2.0.0;python_version=='2.7' # BSD
+sphinx>=1.8.0,!=2.1.0 # BSD
-sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD

releasenotes/notes/drop-py-2-7-5ef11499fe79e1ca.yaml

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

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

@@ -1,7 +1,8 @@
 [tox]
-envlist = pypy,py27,py37,pep8
+envlist = pypy,py37,pep8
-minversion = 2.0
+minversion = 3.1.1
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
 basepython = python3