Update main.yaml

Update supported python versions.

.github/workflows/main.yaml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [2.7, 3.5, 3.6, 3.7, 3.8]
+        python-version: [3.7, 3.8, 3.9, 3.10, 3.11, 3.12]
 
     steps:
     - name: Checkout code