Validate the file list based on the amount of files in the list.

The ListCountValidator extension can be configured with the ListCountValidatorOptions object. 

import { defineFilePond } from 'filepond';
import { locale } from 'filepond/locales/en-gb.js';
import { ListCountValidator } from 'filepond/extensions/list-count-validator.js';

defineFilePond({
    locale,
    extensions: [
        // Add the ListCountValidator extension and configure with ListCountValidatorOptions object
        [ListCountValidator, {
            maxFiles: 3
        }]
    ]
})