update build env

Author: stefanseefeld

.appveyor.yml

@@ -14,10 +14,15 @@ environment:
       PYTHON_VERSION: "3.6.x"
       PYTHON_ARCH: "64"
 
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      PYTHON: "C:\\Python36-x64"
+      PYTHON_VERSION: "3.6.x"
+      PYTHON_ARCH: "64"
+
 install:
   - curl -LfsS -o vswhere.exe https://github.com/Microsoft/vswhere/releases/download/2.3.7/vswhere.exe
   - "set PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
-  - "%CMD_IN_ENV% pip install -U pytest pytest-asyncio mock six pyyaml"
+  - "%CMD_IN_ENV% pip install -U pytest pytest-asyncio mock pyyaml"
 
 # At this point we are only building and testing the asyncio-based scheduler on Windows.
 build: off

.travis.yml

@@ -1,20 +1,22 @@
 dist: xenial
 language: python
 
-matrix:
+jobs:
   include:
     - os: linux
-      python: "3.6"
+      python: 3.6
       env: flake8=true
     - os: linux
-      python: "3.6"
+      python: 3.6
       env: doc=true
     - os: linux
-      python: "3.6"
-      env: PYTHON=3
+      python: 3.6
+    - os: linux
+      python: 3.7
+    - os: linux
+      python: 3.8
     - os: osx
       language: generic
-      env: PYTHON=3
 
 addons:
   apt:
@@ -35,7 +37,7 @@ before_install:
        fi
 
 install:
-  - pip install -U pytest pytest-asyncio mock six flake8 pyyaml codecov pytest-cov
+  - pip install -U pytest pytest-asyncio mock flake8 pyyaml codecov pytest-cov
   - if [ "$doc" = true ]; then pip install -U sphinx sphinx-argparse pygraphviz; fi
 
 script: