Dropping the py35 testing

All the integration testing has been moved to
Bionic now[1] and py3.5 is not tested runtime for
Train or stable/stein[2].

As per below ML thread, we are good to drop the py35
testing now:
http://lists.openstack.org/pipermail/openstack-discuss/2019-April/005097.html

[1] http://lists.openstack.org/pipermail/openstack-discuss/2019-April/004647.html
[2]
https://governance.openstack.org/tc/reference/runtimes/stein.html
https://governance.openstack.org/tc/reference/runtimes/train.html

Change-Id: I50ee998ebcf20dff9aa6238b254021d6d2378448

.zuul.yaml

@@ -39,7 +39,7 @@
 - project:
     templates:
       - openstack-python-jobs-neutron
-      - openstack-python35-jobs-neutron
+      - openstack-python36-jobs-neutron
       - openstack-python36-jobs
       - check-requirements
       - publish-openstack-docs-pti
@@ -56,10 +56,6 @@
             required-projects:
               - openstack/neutron
               - openstack/networking-sfc
-        - openstack-tox-py35:
-            required-projects:
-              - openstack/neutron
-              - openstack/networking-sfc
         - openstack-tox-py36:
             required-projects:
               - openstack/neutron
@@ -77,10 +73,6 @@
             required-projects:
               - openstack/neutron
               - openstack/networking-sfc
-        - openstack-tox-py35:
-            required-projects:
-              - openstack/neutron
-              - openstack/networking-sfc
         - openstack-tox-py36:
             required-projects:
               - openstack/neutron

setup.cfg

@@ -15,7 +15,7 @@ classifier =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
 
 [files]
 packages =

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.6
-envlist = py35,py27,pypy,pep8
+envlist = py36,py27,pypy,pep8
 skipsdist = True
 
 [testenv]