Add support for sending documents

tests/TgBotLib/Methods/SendDocumentTest.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace TgBotLib\Methods;
+
+use PHPUnit\Framework\TestCase;
+use TgBotLib\Bot;
+use TgBotLib\Enums\Types\ParseMode;
+use TgBotLib\Objects\LinkPreviewOptions;
+use TgBotLib\Objects\Message;
+
+class SendDocumentTest extends TestCase
+{
+    const string TEST_DOCUMENT_PATH = __DIR__ . DIRECTORY_SEPARATOR . 'sample' . DIRECTORY_SEPARATOR . 'password.txt';
+    private static Bot $bot;
+
+    /**
+     * @return void
+     */
+    public static function setUpBeforeClass(): void
+    {
+        self::$bot = new Bot(BOT_TOKEN);
+    }
+
+    public function testSendDocument(): void
+    {
+        $result = self::$bot->sendDocument(
+            chat_id: TEST_CHAT_ID,
+            document: self::TEST_DOCUMENT_PATH,
+            caption: 'Test Unit: testSendDocument',
+        );
+
+        $this->assertInstanceOf(Message::class, $result);
+        $this->assertEquals('Test Unit: testSendDocument', $result->getCaption());
+    }
+}

tests/TgBotLib/Methods/sample/password.txt

@@ -0,0 +1,10 @@
+The Plague: Our recent unknown intruder penetrated using the superuser account, giving him access to our whole system.
+
+Margo: Precisely what you're paid to prevent.
+
+The Plague: Someone didn't bother reading my carefully prepared memo on commonly-used passwords. Now, then, as I so
+meticulously pointed out, the four most-used passwords are: love, sex, secret, and...
+
+Margo: [glares at The Plague]
+
+The Plague: god. So, would your holiness care to change her password?