Add support for worker options

[FallingSnow]

https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker

var myWorker = new Worker(aURL, options);

Worker supports an options variable being passed to the worker constructor. These options are required to enable es modules.

offscreen-canvas/create-worker.js

Line 3 in ef3ac05

var worker = new Worker(workerUrl)

[ai]

Please send PR