[ussuri][goal] Updates for python 2.7 drop

OpenStack is dropping the py2.7 support in ussuri cycle except
swift and sorlets which is exception approved in this goal.

Somehow this repo is left to remove the py2.7 requirement
and setup.cfg file cleanup.

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

Also drop the stable/queens|rocky py2 jobs because octavia-tempest-plugin master
code cannot test them because of py2 drop. They are also Extended Maintainance
state so it is ok to not test them on master. Same way Tempest and other
plugins did
- https://review.opendev.org/#/c/722183/

Change-Id: I9b20229a25dc9752e4a813709f0b67bbd104faa5
diff --git a/setup.cfg b/setup.cfg
index 5da1d1d..3e5d216 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -6,6 +6,7 @@
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/octavia-tempest-plugin/latest/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,10 +14,11 @@
     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 :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
 
 [global]
 setup-hooks =
@@ -26,14 +28,6 @@
 packages =
     octavia_tempest_plugin
 
-[build_sphinx]
-source-dir = doc/source
-build-dir = doc/build
-all_files = 1
-
-[upload_sphinx]
-upload-dir = doc/build/html
-
 [compile_catalog]
 directory = octavia_tempest_plugin/locale
 domain = octavia_tempest_plugin