Drop python 2 support and testing

This is part of Ussuri goal tracked for Neutron stadium at:
https://etherpad.openstack.org/p/neutron-train-zuulv3-py27drop

Change-Id: I46894fefe681d7e84343a633a803c87e1e88cfb6

releasenotes/notes/drop-py27-support-c426980520444bfa.yaml

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

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://pypi.org/project/ovsdbapp/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,8 +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

@@ -1,10 +1,9 @@
 [tox]
-minversion = 2.0
+minversion = 3.1.1
-envlist = py27,py37,pypy,pep8
+envlist = py36,py37,pypy,pep8
 skipsdist = True
 
 [testenv]
-basepython = python3
 usedevelop = True
 setenv =
    VIRTUAL_ENV={envdir}

zuul.d/project.yaml

@@ -2,7 +2,6 @@
     templates:
       - check-requirements
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
     check: