chore: Update docs

examples/VoiceMessage.js

@@ -0,0 +1,21 @@
+const { Client, MessageAttachment } = require('../src/index');
+const client = new Client();
+
+client.on('ready', async () => {
+  console.log(`${client.user.username} is ready!`);
+  const channel = client.channels.cache.get('channel_id');
+  const attachment = new MessageAttachment(
+    './test.mp3', // path file
+    'random_file_name.ogg', // must be .ogg
+    {
+      waveform: '=',
+      duration_secs: 1, // any number you want
+    },
+  );
+  channel.send({
+    files: [attachment],
+    flags: 'IS_VOICE_MESSAGE',
+  });
+});
+
+client.login('token');