[3.0] Introduce Options class representing supported resolv.conf options

The two current supported options, `attempts` and `timeout`, have their min (assumed to be `1`), max, and default value as specified on https://man7.org/linux/man-pages/man5/resolv.conf.5.html set.

Author: WyriHaximus

src/Config/Options.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace React\Dns\Config;
+
+final class Options
+{
+    /**
+     * @var int<1, 5>
+     */
+    public $attempts = 2;
+    /**
+     * @var int<1, 30>
+     */
+    public $timeout = 5;
+}