'maxStackSize' has private access in 'net.minecraft.item.Item.Properties'

So I'm trying to make an addon for Mr. Crayfish's Gun mod, what I'm trying to achieve right now is to add a new gun, but I got this error while adding the max stack size property to the item and I don't know how to get around it:

'maxStackSize' has private access in 'net.minecraft.item.Item.Properties'

The line of code is this one:

    public static final Item.Properties genericProperties = new Item.Properties().maxStackSize(1).group(MoGuns.GROUP);

And the whole code is this:

package ttv.alanormiga.moguns.core.registry;

import ttv.alanormiga.moguns.core.MoGuns;
import com.mrcrayfish.guns.item.GunItem;
import net.minecraft.item.Item;
import net.minecraftforge.fml.RegistryObject;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;

public class ItemRegistry {
    public static final DeferredRegister<Item> ITEMS = DeferredRegister.create(ForgeRegistries.ITEMS, MoGuns.ID);
    public static final Item.Properties genericProperties = new Item.Properties().maxStackSize(1).group(MoGuns.GROUP);

    public static final RegistryObject<Item> SCAR = ITEMS.register("scar", () -> new GunItem(genericProperties));

}

Also here is my github repo:

https://github.com/AlanorMiga/MoGuns

Any help is greatly appreciated! Thanks in advance!