Merge branch '3.11' into develop

PR #285

* 3.11:
  Add testing for Python 3.11

Author: jamesls

.github/workflows/run-tests.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: [3.7, 3.8, 3.9, "3.10"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11-dev"]
 
     steps:
     - uses: actions/checkout@v2

setup.py

@@ -28,6 +28,7 @@
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
     ],