In the documentation of the dotenv component (https://symfony.com/doc/current/components/dotenv.html) it says:
You should never store a .env file in your code repository as it might contain sensitive information; create a .env.dist file with sensible defaults instead.
However since november 2018 changes (https://symfony.com/doc/current/configuration/dot-env-changes.html) the .env.dist file is no longer used and is replaced by the combination of .env in the repo and .env.local on your local environment.

The documentation should be updated to reflect these changes