Add py38 to see if coverage is OK

Author: nicoddemus

.github/workflows/main.yml

@@ -39,7 +39,7 @@ jobs:
 #          "ubuntu-py37",
 #          "ubuntu-py37-pluggy",
 #          "ubuntu-py37-freeze",
-#          "ubuntu-py38",
+          "ubuntu-py38",
           "ubuntu-pypy3",
 
 #          "macos-py37",