liltoon hasn't been updated for it yet and it probably will get updated soon but if you want light volumes 2.0 right away you can just add the light volume official package to your project,
it will update the cginc and it will just work (adding it to liltoons package is all the update will do in regards to LV2.0 anyway)

>add light volume package
1. Go to my VPM Listing web page: https://redsim.github.io/vpmlisting/
2. Press "Add to VCC"
3. Confirm adding in the popup dialog window