Adds custom item properties, for now it is only submerged predicate that lets items change when the player is underwater. More properties coming soon.
example with [Weskerson's torches](https://modrinth.com/resourcepack/weskersons-torches)
on modrinth:https://modrinth.com/mod/rpputils
how to use
on
```
minecraft/items
```
```
{
"model": {
"type": "minecraft:condition",
"property": "rj:submerged",
"on_true": {
"type": "minecraft:model",
"model": "minecraft:item/underwater_item"
},
"on_false": {
"type": "minecraft:model",
"model": "minecraft:item/normal_item"
}
}
}
```
