Add support for Python 3.7-3.9

Author: hugovk

appveyor.yml

@@ -1,6 +1,8 @@
 # AppVeyor.com is a Continuous Integration service to build and run tests under
 # Windows
 
+image: Visual Studio 2019
+
 environment:
   matrix:
      - PYTHON: "C:\\Python27"
@@ -11,6 +13,12 @@ environment:
      - PYTHON: "C:\\Python35-x64"
      - PYTHON: "C:\\Python36"
      - PYTHON: "C:\\Python36-x64"
+     - PYTHON: "C:\\Python37"
+     - PYTHON: "C:\\Python37-x64"
+     - PYTHON: "C:\\Python38"
+     - PYTHON: "C:\\Python38-x64"
+     - PYTHON: "C:\\Python39"
+     - PYTHON: "C:\\Python39-x64"
 
 install:
   - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"

setup.py

@@ -18,6 +18,9 @@
                    'Programming Language :: Python :: 3.4',
                    'Programming Language :: Python :: 3.5',
                    'Programming Language :: Python :: 3.6',
+                   'Programming Language :: Python :: 3.7',
+                   'Programming Language :: Python :: 3.8',
+                   'Programming Language :: Python :: 3.9',
                    ],
       keywords='cycle kwargs',
       )