run tests in Python 3.10

Author: thomasballinger

.github/workflows/build.yaml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        python-version: [3.6, 3.7, 3.8, 3.9, pypy3]
+        python-version: [3.6, 3.7, 3.8, 3.9, "3.10", pypy3]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}