tRNS not handled properly, causing a error during decoding gray scale images.

[blvd20]

https://github.com/image-js/fast-png/blob/9563e3dcc66bd402c3a969dfe1027bf897ab9296/src/PngDecoder.ts#L212

At least, there should have a this.skip(length).

[targos]

Can you share an image that causes this issue so we can use it in unit tests?

[blvd20]

@targos

[targos]

Thanks. Fixed in version 6.2.0.

The field is now correctly decoded and its values can be read from img.transparency.