sample.php

<?php
/**
 * Plugin Name:       Sample Plugin
 * Description:       A sample plugin
 * Version:           1.0
 */

require_once __DIR__ . '/vendor/autoload.php';

$plugin = new \Sample\Loader(__DIR__, plugin_dir_url(__FILE__));
$plugin->init();

register_activation_hook(__FILE__, [\Sample\Loader::class, 'activatePlugin']);
register_deactivation_hook(__FILE__, [\Sample\Loader::class, 'deactivatePlugin']);