✨ Use Pydantic BaseSettings for config settings (#87)

* Use Pydantic BaseSettings for config settings

* Update fastapi dep to >=0.47.0 and email_validator to email-validator

* Fix deprecation warning for Pydantic >=1.0

* Properly support old-format comma separated strings for BACKEND_CORS_ORIGINS

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

{{cookiecutter.project_slug}}/docker-compose.test.yml

@@ -10,6 +10,7 @@ services:
       - env-postgres.env
     environment:
       - SERVER_NAME=backend
+      - SERVER_HOST=http://${DOMAIN}
   backend:
     environment:
       # Don't send emails during testing