Added Django 4.0 to test matrix. (#1072)

* Added Django 4.0 to test matrix.
* Switched to `django-admin` (without `.py` suffix) for test commands.
  The old aliases are Removed in Django 4.0.

.github/workflows/ci.yml

@@ -51,6 +51,12 @@ jobs:
           - python: 3.9
             toxenv: py39-3.2.X
 
+          - python: 3.8
+            toxenv: py38-4.0.X
+          - python: 3.9
+            toxenv: py39-4.0.X
+
+
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2

Makefile

@@ -7,7 +7,7 @@ flake8:
 	flake8 compressor --ignore=E501,E128,E701,E261,E301,E126,E127,E131,E402,W503
 
 runtests:
-	coverage run --branch --source=compressor `which django-admin.py` test --settings=compressor.test_settings compressor
+	coverage run --branch --source=compressor `which django-admin` test --settings=compressor.test_settings compressor
 
 coveragereport:
 	coverage report --omit=compressor/test*

tox.ini

@@ -4,6 +4,7 @@ envlist =
     {py36,py37,py38,py39}-3.0.X
     {py36,py37,py38,py39}-3.1.X
     {py36,py37,py38,py39}-3.2.X
+    {py38,py39}-4.0.X
 [testenv]
 basepython =
     py35: python3.5
@@ -16,11 +17,12 @@ setenv =
     CPPFLAGS=-O0
 whitelist_externals = /usr/bin/make
 commands =
-    django-admin.py --version
+    django-admin --version
     make test
 deps =
     2.2.X: Django>=2.2,<2.3
     3.0.X: Django>=3.0,<3.1
     3.1.X: Django>=3.1,<3.2
     3.2.X: Django>=3.2,<4.0
+    4.0.X: Django>=4.0a1,<5.0
     -r{toxinidir}/requirements/tests.txt