Change default target to LTS

[ayuhito]

I think having the default target to be reliant on process.versions.node creates a lot of inconsistency especially if you use a multitude of environments such as local and CI.

To fit closer to the paradigm of zero-config, it might be better for the bundler to default to Node LTS instead for best practices.

I'm not sure if this should be considered a breaking change considering the existing setup already led to inconsistent bundles.

[privatenumber]

I'm OK with that but we'll need a trusted API to get the latest Node version. Ideally an npm package that contains Node.js versions or something so that there's no loading time during build.

[ayuhito]

Isn't it just changing this line here from node${process.versions.node} to node14. Or am I missing something here? I'll be happy to PR it just to start getting my hands involved with this repo if that's the case.

I do think we should manually set the target and update the LTS target versions ourselves, so every time the default target changes we can mark it as a breaking change.