Rename Django's dev branch to main. (#932)

More information: https://groups.google.com/g/django-developers/c/tctDuKUGosc/ Refs: django/django#14048

Author: jezdez

tox.ini

@@ -4,7 +4,7 @@ envlist =
  docs,
  py{36,37,38,39}-dj{31,30,22},
  py35-dj{22},
- py{38,39}-djmaster,
+ py{38,39}-djmain,
 
 [gh-actions]
 python =
@@ -30,7 +30,7 @@ deps =
  dj22: Django>=2.2,<3
  dj30: Django>=3.0,<3.1
  dj31: Django>=3.1,<3.2
-djmaster: https://github.com/django/django/archive/master.tar.gz
+djmain: https://github.com/django/django/archive/main.tar.gz
  djangorestframework
  oauthlib>=3.1.0
  coverage
@@ -42,7 +42,7 @@ deps =
 passenv =
  PYTEST_ADDOPTS
 
-[testenv:py{38,39}-djmaster]
+[testenv:py{38,39}-djmain]
 ignore_errors = true
 ignore_outcome = true