README.md: Colorize YAML block, fix macOS capitalization and remove d…

…eprecated compose version (#847)

README.md

@@ -49,7 +49,7 @@ Rewrite of [Sonixd](https://github.com/jeffvli/sonixd).
 
 Download the [latest desktop client](https://github.com/jeffvli/feishin/releases). The desktop client is the recommended way to use Feishin. It supports both the MPV and web player backends, as well as includes built-in fetching for lyrics.
 
-#### MacOS Notes
+#### macOS Notes
 
 If you're using a device running macOS 12 (Monterey) or higher, [check here](https://github.com/jeffvli/feishin/issues/104#issuecomment-1553914730) for instructions on how to remove the app from quarantine.
 
@@ -74,8 +74,7 @@ docker run --name feishin -p 9180:9180 feishin
 
 To install via Docker Compose use the following snippit. This also works on Portainer.
 
-```
-version: '3'
+```yaml
 services:
   feishin:
     container_name: feishin