Update pythonpackage.yml

Author: jhavl

.github/workflows/pythonpackage.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         os: [windows-latest, ubuntu-latest, macos-latest]
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, "3.10"]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}