doc: update compose.override.yaml patch content in tls.md

Author: 7-zete-7

docs/tls.md

@@ -34,7 +34,7 @@ For instance, to use self-signed certificates created with [mkcert](https://gith
         # ...
       volumes:
     +    - ./frankenphp/certs:/etc/caddy/certs:ro
-        - ./public:/app/public:ro
+        - ./:/app
     ```
 5. Restart your `php` service