Spritato is a 3rd party alternative to the official export script to export your PSD file to spine.
It is a standalone app released on Microsoft Store for Windows platform. You do not need to have Photoshop to run it.
If you are interested, here is a few tutorials for you to learn more about this app.
Tutorial 1 - The basic workflow demonstration.
Tutorial 2 - Using the exclusive Pixel Adjustment Layer.
Tutorial 3 - Exporting with skin settings.