Update Google Cast integration (#13269)

source/_integrations/cast.markdown

@@ -34,6 +34,57 @@ Home Assistant Cast requires your Home Assistant installation to be accessible v
 
 </div>
 
+## Casting other apps
+
+### YouTube
+
+- `app_name`: `youtube`
+- `media_id`: YouTube video ID
+
+Optional:
+- `enqueue`: Enqueue only
+- `playlist_id`: Play video with `media_id` from this playlist
+
+```yaml
+'cast_youtube_to_my_chromecast':
+  alias: Cast YouTube to My Chromecast
+  sequence:
+  - data:
+      entity_id: media_player.my_chromecast
+      media_content_type: cast
+      media_content_id: '
+        {
+          "app_name": "youtube",
+          "media_id": "dQw4w9WgXcQ"
+        }'
+    service: media_player.play_media
+```
+
+### [Supla](https://www.supla.fi/)
+
+Example values to cast the item at https://www.supla.fi/audio/3601824
+
+- `app_name`: `supla`
+- `media_id`: Supla item ID
+
+Optional:
+- `is_live`: Item is a livestream
+
+```yaml
+'cast_supla_to_my_chromecast':
+  alias: Cast supla to My Chromecast
+  sequence:
+  - data:
+      entity_id: media_player.my_chromecast
+      media_content_type: cast
+      media_content_id: '
+        {
+          "app_name": "supla",
+          "media_id": "3601824"
+        }'
+    service: media_player.play_media
+```
+
 ## Advanced use
 
 ### Manual configuration