Reconfigure GitHub test matrix for Django 3.2

Drop unsupported Python versions
and run in experimental mode

pip failures fail the whole pipeline
when a package has mismatching version specifiers

.github/workflows/test.yml

@@ -10,11 +10,21 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ['3.6', '3.7', '3.8', '3.9', 'pypy3']
-        django-version: ['2.2', '3.0', '3.1', 'dev']
+        django-version: ['2.2', '3.0', '3.1']
         # Tox configuration for QA environment
         include:
           - python-version: '3.8'
             django-version: 'qa'
+          # Django >= 3.2 only supports >= Python 3.8
+          - python-version: '3.8'
+            django-version: 'dev'
+            experimental: true
+          - python-version: '3.9'
+            django-version: 'dev'
+            experimental: true
+          - python-version: 'pypy3'
+            django-version: 'dev'
+            experimental: true
 
     steps:
     - uses: actions/checkout@v2

pyproject.toml

@@ -11,7 +11,8 @@ legacy_tox_ini = """
 [tox]
 envlist =
     py38-djqa
-    py{36,37,38,39,py3}-dj{22,30,31,dev}
+    py{36,37,38,39,py3}-dj{22,30,31}
+    py{38,39,py3}-dj{dev}
 
 [gh-actions]
 python =
@@ -43,7 +44,7 @@ setenv =
     PYTHONDONTWRITEBYTECODE=1
 
 # Django development version is allowed to fail the test matrix
-[testenv:py{36,37,38,39,py3}-djdev]
+[testenv:py{38,39,py3}-dj{dev}]
 ignore_errors = true
 ignore_outcome = true