test only active python releases

as per https://www.python.org/downloads/

Author: attwad

.github/workflows/python-test.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, 3.10, 3.11]
 
     steps:
     - uses: actions/checkout@v2