Deps: update to elasticsearch8

[JacobCoffee]

These would need to be changed

• pythondotorg/pydotorg/settings/local.py

  Line 29 in 82682b0

  'ENGINE': 'haystack.backends.elasticsearch7_backend.Elasticsearch7SearchEngine',

• pythondotorg/pydotorg/settings/cabotage.py

  Line 29 in 624dc3a

  'ENGINE': 'haystack.backends.elasticsearch7_backend.Elasticsearch7SearchEngine',

Originally posted by @JacobCoffee in #2582 (comment)

[ewdurbin]

Seems alright, we are running elasticsearch 8.x in prod so this should be good to go.

Might be worth adding an ES container to docker-compose.yml to be sure

[JacobCoffee]

Dependant on django-haystack/django-haystack#1980