chore: improves type coverage

src/Contracts/Bootstrapper.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Contracts;
+
+/**
+ * @internal
+ */
+interface Bootstrapper
+{
+    /**
+     * Boots the bootstrapper.
+     */
+    public function boot(): void;
+}