Component that handles auto-generating 2D Shadow caster shapes for your Tilemap and applies them.
Simply extract this repo to the Root of your Project, and then add the TilemapShadowCaster2D component to your Tilemap object and it will do its job.
It has several options to control the settings of the generated Shadow Casters, including an option to Composite them into a single caster so that separate islands of your Tilemap do not cast shadows onto eachother.