custom_mc_advancements/data/canopy/advancements/get_sed.json

{
    "display": {
        "icon": {
            "item": "minecraft:wheat_seeds"
        },
        "title": "Get sed",
        "description": "Obtain some sed",
        "frame": "task",
        "announce_to_chat": true
    },
    "parent": "canopy:root",
    "criteria": {
        "have_sed": {
            "trigger": "minecraft:inventory_changed",
            "conditions": {
                "items": [{
                    "item": "minecraft:wheat_seeds"
                }]
            }
        }
    }
}