Updated test matrix -- Django Dev dropped support for Python3.6 and 3.7 (#800)

Author: smithdc1

.github/workflows/test.yml

@@ -13,6 +13,12 @@ jobs:
         python-version: ['3.6', '3.7', '3.8', '3.9']
         django-version: ['2.2', '3.0', '3.1', 'dev']
 
+        exclude:
+        - python-version: '3.6'
+          django-version: 'dev'
+        - python-version: '3.7'
+          django-version: 'dev'
+
     services:
 
       postgres:

tox.ini

@@ -1,6 +1,7 @@
 [tox]
 envlist =
-    py{36,37,38,39}-dj{22,30,31,dev}-{sqlite3,postgres,mysql,mariadb},
+    py{36,37,38,39}-dj{22,30,31}-{sqlite3,postgres,mysql,mariadb},
+    py{38,39}-dj{dev}-{sqlite3,postgres,mysql,mariadb},
     docs,
     lint