Don't pin pexpect to a specific version.
Don't pin pexpect to a specific version.

Since pexpect is managed outside of the project's requirements.txt file,
we should not pin it to a specific version. Doing so results in it never
being updated.

The workaround that requires us to install pexpect should become
unnecessary after we upgrade to Django 3.0:
https://docs.djangoproject.com/en/3.0/ref/django-admin/#createsuperuser

pydata/conf_site,pydata/conf_site,pydata/conf_site