Include python 3.10 in CI (HunterMcGushion#92)

Author: MiWeiss

.github/workflows/python-package.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [macos-latest, windows-latest, ubuntu-latest]
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8, 3.9, "3.10"]
 
     steps:
       - uses: actions/checkout@v2