app.py: increase concurrency

app.py

@@ -148,4 +148,4 @@ with gr.Blocks(css=css) as demo:
     )
 
 
-demo.queue(default_concurrency_limit=8, max_size=10, api_open=False).launch(max_threads=32, show_api=False)
+demo.queue(default_concurrency_limit=10, max_size=12, api_open=False).launch(max_threads=32, show_api=False)