[5.1.x] Specified "django" repository for twine call in docs/internals/howto-release-django.txt.

It's necessary to specify a repository for `.pypirc` user configurations
with multiple per-project PyPI tokens.

Follow up to 26aedbb.

Backport of 0dc6149 from main.

Author: felixxm

docs/internals/howto-release-django.txt

@@ -517,7 +517,7 @@ Now you're ready to actually put the release out there. To do this:
 
    .. code-block:: shell
 
-       $ twine upload dist/*
+       $ twine upload --repository django dist/*
 
 #. Go to the `Add release page in the admin`__, enter the new release number
    exactly as it appears in the name of the tarball