Thanks for providing us with the code.
From what I can see, you just added the spine-pixi runtime to the package.json, but you are still using pixi-spine. spine-pixi is not yet compatible with Pixi 8, so if you want to use the latest version, you have to use pixi-spine as you are doing right now.
Unfortunately, as far as I can see from the pixi-spine repository, clipping attachments are not yet fully functional. I suppose the best thing you can do to work with clipping attachments is to downgrade to version 7 of Pixi, right now.
