Zopfli compress JS files

[johanbrandhorst]

Hi!

This is a super cool idea, and I really like it, especially the package splitting. However, further gains in terms of bandwidth can be had by Zopfli or Gzip compressing the JS files. In my testing I achieve about 80% compression rate using Zopfli with go-zopfli and default settings.

See https://github.com/johanbrandhorst/grpcweb-example/blob/master/client/app.go#L11 for an example of this in use.

[johanbrandhorst]

I just realised they're already compressed, my browser is getting brotli back but I assume you've got gzip covered as well, ignore me!