Drop py27 support

Per the Ussuri cycle goal, this drops py27 testing and support.

https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Change-Id: I0c525eb48270494e8171042e56e14867c53e5af3
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

.zuul.yaml

@@ -4,7 +4,6 @@
       - designate-devstack-jobs
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - openstackclient-plugin-jobs
       - publish-openstack-docs-pti

releasenotes/notes/drop-py2-c4e50d006fa4446c.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. The last release of python-designateclient
+    to support Python 2.7 is 3.1. The minimum version of Python now supported
+    is Python 3.6.

setup.cfg

@@ -14,8 +14,6 @@ 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

@@ -1,9 +1,14 @@
 [tox]
-envlist = py27,py37,flake8
-minversion = 2.0
+envlist = py36,py37,flake8
+minversion = 3.1.0
 skipsdist = True
+skip_missing_interpreters = true
+# this allows tox to infer the base python from the environment name
+# and override any basepython configured in this file
+ignore_basepython_conflict = true
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
@@ -25,7 +30,6 @@ commands =
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 
 [testenv:docs]
-basepython = python3
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
@@ -33,19 +37,15 @@ deps =
 commands = sphinx-build -b html doc/source doc/build/html
 
 [testenv:flake8]
-basepython = python3
 commands = flake8
 
 [testenv:pep8]
-basepython = python3
 commands = flake8
 
 [testenv:pyflakes]
-basepython = python3
 commands = flake8
 
 [testenv:cover]
-basepython = python3
 setenv =
     PYTHON=coverage run --source designateclient --parallel-mode
 commands =
@@ -55,7 +55,6 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:functional]
@@ -68,8 +67,15 @@ passenv = OS_STDOUT_CAPTURE
           OS_DEBUG
           TEMPEST_CONFIG
 
+[testenv:functional-py36]
+setenv =
+  {[testenv:functional]setenv}
+
+[testenv:functional-py37]
+setenv =
+  {[testenv:functional]setenv}
+
 [testenv:releasenotes]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
@@ -89,7 +95,6 @@ builtins = _
 exclude = .venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,build,tools
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt