Update app.py

Allow simultaneous usage.

app.py

@@ -771,7 +771,7 @@ with gr.Blocks(theme=gr.themes.Soft()) as iface:
             *txt2vid_advanced,
         ],
         outputs=txt2vid_output,
-        concurrency_limit=1,
+        concurrency_limit=None,
         concurrency_id="generate_video",
     )
 
@@ -789,7 +789,7 @@ with gr.Blocks(theme=gr.themes.Soft()) as iface:
             *img2vid_advanced,
         ],
         outputs=img2vid_output,
-        concurrency_limit=1,
+        concurrency_limit=None,
         concurrency_id="generate_video",
     )