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.

https://github.com/ai/offscreen-canvas/blob/ef3ac052cf3db22dd370ab9578fe5b0b982a9124/create-worker.js#L3

[ai]

Please send PR