Update bsconfig and package.json for 3.0.0

[wokalski]

This PR updates the bucklescript-related files. Btw everything still works well in runtime 👍. Thanks for the maintenance of this repo. For the automated publish script we'd need an npm token of somebody. I used mine for the runtime so far but I can add someone to the repo. I also can add mine to the repo but it'd require giving me some access to the settings.