change on push CI

Author: abenseny

.github/workflows/on-push.yml

@@ -44,7 +44,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python: [3.6, 3.7, 3.8]
+        python: [3.7, 3.8, 3.9]
     steps:
     - uses: actions/checkout@v1
     - name: Install Python dependencies