Remove duplicate version mapping.

Author: jezdez

tox.ini

@@ -3,11 +3,11 @@ envlist =
     py{36,37,38,39}-dj{21,22,30,31,master}
     flake8
 
-[travis]
+[gh-actions]
 python =
     3.6: py36
     3.7: py37
-    3.8: py38
+    3.8: py38, flake8
     3.9: py39
 
 [testenv]
@@ -46,9 +46,3 @@ ignore =
     W503  ; line break before binary operator
     E402  ; module level import not at top of file
     E501  ; line too long
-
-[gh-actions]
-python =
-    3.6: py36
-    3.7: py37
-    3.8: py38, flake8