build on 3.10

Author: jschlyter

.github/workflows/test.yml

@@ -14,6 +14,7 @@ jobs:
           - 3.7
           - 3.8
           - 3.9
+          - 3.10
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}