Drop python 2.7 support and testing

OpenStack dropped py2.7 support in Ussuri cycle.

octavia-tempest-plugin is ready with python 3 so it's ok to drop
python 2.7 support.

Also added requirements test support to tox.ini

Modeled on similar neutron-tempest-plugin change.

Change-Id: Iba286366a8d6ce75b3a73756c5bdc70c77723232

requirements.txt

@@ -4,7 +4,6 @@
 
 cryptography>=2.1 # BSD/Apache-2.0
 python-dateutil>=2.5.3 # BSD
-ipaddress>=1.0.17;python_version<'3.3' # PSF
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
 oslo.log>=3.36.0  # Apache-2.0

tox.ini

@@ -1,9 +1,11 @@
 [tox]
-minversion = 2.0
+minversion = 3.1
 envlist = pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install {opts} {packages}
 setenv =
@@ -16,15 +18,12 @@ commands =
   stestr slowest
 
 [testenv:pep8]
-basepython = python3
 commands = flake8
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv =
   {[testenv]setenv}
   PYTHON=coverage run --source octavia_tempest_plugin --parallel-mode
@@ -39,7 +38,6 @@ commands =
   coverage xml -o cover/coverage.xml
 
 [testenv:docs]
-basepython = python3
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt
@@ -50,7 +48,6 @@ commands =
   sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-basepython = python3
 deps = {[testenv:docs]deps}
 whitelist_externals =
   make
@@ -61,7 +58,6 @@ commands =
   make -C doc/build/pdf
 
 [testenv:releasenotes]
-basepython = python3
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt
@@ -70,7 +66,6 @@ commands =
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:debug]
-basepython = python3
 commands = oslo_debug_helper {posargs}
 
 [flake8]
@@ -86,9 +81,15 @@ import-order-style = pep8
 enable-extensions=H106,H203,H204,H205,H904
 
 [testenv:genconfig]
-basepython = python3
 whitelist_externals = mkdir
 commands =
          mkdir -p etc
          oslo-config-generator --output-file etc/octavia.tempest.conf.sample \
          --namespace tempest.config
+
+[testenv:requirements]
+deps =
+  -egit+https://opendev.org/openstack/requirements#egg=openstack-requirements
+whitelist_externals = sh
+commands =
+    sh -c '{envdir}/src/openstack-requirements/playbooks/files/project-requirements-change.py --req {envdir}/src/openstack-requirements --local {toxinidir} master'