fix: Formatter config depending in Mix breaks formatter

[odarriba]

When using error_tracker in other projects and telling the formatter to import the config from :error_tracker dependency causes ExpertLS to break and not applying styles properly.

Debugging locally I found that it is because of the Elixir version autodetect we use. This pull request is removing that, as we:

• are not updating it regularly
• if we import the config on projects using error_tracker we do not need to get the minimum elixir version on that project.

[crbelaus]

🚀