ci: Transition to CircleCI 2.0, test against python 3.6 instead of 3.5

.circleci/config.yml

@@ -0,0 +1,39 @@
+version: 2
+jobs:
+  py27:
+    docker:
+      - image: circleci/python:2.7.14-stretch
+    environment:
+      - TOX_ENV=py27
+      - INTEGRATION_TEST_REPO_NAME=github-release-bot/github-release-test-py2
+      - INTEGRATION_TEST_GIT_USER_NAME=github-release-bot
+      - INTEGRATION_TEST_GIT_USER_EMAIL=github-release-bot@users.noreply.github.com
+    steps:
+    - checkout
+    - run:
+        name:
+        command: |
+          pip install -r requirements-dev.txt
+          tox -e ${TOX_ENV}
+  py36:
+    docker:
+      - image: circleci/python:3.6.5-stretch
+    environment:
+      - TOX_ENV=py36
+      - INTEGRATION_TEST_REPO_NAME=github-release-bot/github-release-test-py3
+      - INTEGRATION_TEST_GIT_USER_NAME=github-release-bot
+      - INTEGRATION_TEST_GIT_USER_EMAIL=github-release-bot@users.noreply.github.com
+    steps:
+    - checkout
+    - run:
+        name:
+        command: |
+          pip install -r requirements-dev.txt
+          tox -e ${TOX_ENV}
+
+workflows:
+  version: 2
+  test-package-publish:
+    jobs:
+      - py27
+      - py36

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,py35
+envlist = py27,py36
 
 [testenv]
 passenv=GITHUB_TOKEN HOME INTEGRATION_TEST_GIT_USER_EMAIL INTEGRATION_TEST_GIT_USER_NAME INTEGRATION_TEST_REPO_NAME TRAVIS