added django 6.0a1 into the CI

Author: auvipy

tox.ini

@@ -2,8 +2,8 @@
 envlist =
        {py310}-{django42,django51,django52}
        {py311}-{django42,django51,django52}
-       {py312}-{django42,django51,django52,djangomain}
-       {py313}-{django51,django52,djangomain}
+       {py312}-{django42,django51,django52,django60,djangomain}
+       {py313}-{django51,django52,django60,djangomain}
        base
        dist
        docs
@@ -19,6 +19,7 @@ deps =
         django50: Django>=5.0,<5.1
         django51: Django>=5.1,<5.2
         django52: Django>=5.2,<6.0
+        django60: Django>=6.0a1,<6.1
         djangomain: https://github.com/django/django/archive/main.tar.gz
         -rrequirements/requirements-testing.txt
         -rrequirements/requirements-optionals.txt