Bum js version

[arthurgiani]

Is your feature request related to a problem? Please describe.
There are a lot of important packages on pub.dev that already depends on js 0.7.1. This package is relying on older js versions, which is causing some upgrade issues.

Describe the solution you'd like
Bum js version to 0.7.1

[AlexMobile-l]

I support it, I also need a new version of js.