Github workflow: run on 3.10 instead of 3.7

Author: eriknyquist

.github/workflows/tests.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       matrix:
         # Run in all these versions of Python
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.8, 3.9, 3.10]
 
     steps:
         # Checkout the latest code from the repo