Missing height and width properties

[jsbien]

I use your tool for https://jsbien.github.io/Parkosz4IIIF/ and I would like to be able to view the documents also with Mirador. I just have been informed that the canvases do not have
height and width properties which they must have - cf. ProjectMirador/mirador#2616 (comment).

[mejackreed]

Looking at https://iiif.io/api/presentation/3.0/#53-canvas

A Canvas must have a rectangular aspect ratio (described with the height and width properties)