Issue 871 removing is-valid with bootstrap4 (#894)
Issue 871 removing is-valid with bootstrap4 (#894)

* Removing usage of is-valid
closes https://github.com/django-crispy-forms/django-crispy-forms/issues/871

maraujop/django-crispy-forms,django-crispy-forms/django-crispy-forms,django-crispy-forms/django-crispy-forms,maraujop/django-crispy-forms