added django40 dep & expanded django3* python versions to all supported

tox.ini

@@ -6,9 +6,10 @@ envlist=
     py{35,36}-django20
     py{35,36,37}-django21
     py{35,36,37}-django22
-    py{36,37,38}-django30
-    py{36,37,38}-django31
-    py{36,37,38}-django32
+    py{36,37,38,39}-django30
+    py{36,37,38,39}-django31
+    py{36,37,38,39,310}-django32
+    py{38,39,310}-django40
 
 [testenv]
 passenv=EMAIL_IMAP_SERVER EMAIL_ACCOUNT EMAIL_PASSWORD EMAIL_SMTP_SERVER
@@ -20,6 +21,7 @@ deps=
     django30: django==3.0.*
     django31: django==3.1.*
     django32: django==3.2.*
+    django40: django==4.0.*
     -r{toxinidir}/test_requirements.txt
 sitepackages=False
 commands=