Add python 3.9-dev to CI tests (#3687)

* Add python 3.9-dev to ci tests

* test integration tests on latest versions of python

.github/workflows/ci.yaml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest]
-        python-version: [2.7, 3.5, 3.6, 3.7, 3.8]
+        python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9-dev]
 
     env:
       PY_COLORS: 1
@@ -82,4 +82,4 @@ jobs:
           python -m pip install tox sphinx
 
       - name: Lint with flake8
-        run: tox -e py-lint
+        run: tox -e py-lint

.github/workflows/integration_test.yaml

@@ -12,10 +12,10 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Set up Python 3.8
+      - name: Set up latest Python version
         uses: actions/setup-python@v2
         with:
-          python-version: 3.8
+          python-version: 3.9-dev
 
       - name: Install base dependencies
         run: |