chore: rollback python version change for now

Author: bryantbiggs

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        python-version: [2.7, 3.6, 3.7, 3.8]
+        python-version: [2.7, 3.6]
     steps:
       - uses: actions/checkout@v2