Put 3.10 in quotes

Author: amanusk

.github/workflows/pythonpackage.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.8, 3.9, 3.10, 3.11]
+        python-version: [3.8, 3.9, '3.10', 3.11]
 
     steps:
     - uses: actions/checkout@v1