add back python 3.8

Author: guzzijones

.github/workflows/tox.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: ["3.6"]
+        python-version: ["3.6", "3.8"]
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2