Update Python versions in tests

Author: tuffnatty

.github/workflows/tests.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9, 3.10, 3.11, 3.12]
+        python-version: [3.7, 3.8, 3.9, "3.10", 3.11, 3.12]
 
     steps:
     - uses: actions/checkout@v2