Suggestion: Provide JuliaFormatter configuration file

I like to use [JuliaFormatter](https://github.com/domluna/JuliaFormatter.jl) to format my Julia source code. This way, I don't have to worry about the details, and the end result is readable and conforms to your standard.

For reference, [this](https://github.com/eschnett/Bernstein.jl/blob/master/.JuliaFormatter.toml) is a configuration I like to use.