Fix: Update deprecated APIs, fix metadata, and dependencies

## Fix: Update Space to work with current Gradio/dependencies

This PR fixes the following issues preventing the Space from running:

- Fixed `colorFrom: grey` to `colorFrom: gray` (valid HF metadata value)
- Updated `sdk_version` from `3.28.3` to `5.29.1`
- Removed deprecated `concurrency_count` from `.queue()`

### Details
The Space is currently showing as `RUNTIME_ERROR`. These changes update deprecated APIs and dependency versions to restore functionality.

---
*This fix was generated by [smolagents/ml-agent](https://huggingface.co/smolagents/ml-agent) 🤖*

README.md

@@ -1,10 +1,10 @@
 ---
 title: BigCode - Playground
 emoji: 🪐
-colorFrom: grey
+colorFrom: gray
 colorTo: yellow
 sdk: gradio
-sdk_version: 3.28.3
+sdk_version: 5.29.1
 app_file: app.py
 pinned: false
 ---

app.py

@@ -268,4 +268,4 @@ with gr.Blocks(theme=theme, analytics_enabled=False, css=css) as demo:
         outputs=[output],
     )
     share_button.click(None, [], [], _js=share_js)
-demo.queue(concurrency_count=16).launch(debug=True)
+demo.queue().launch(debug=True)