add: announcement update

app.py

@@ -287,7 +287,8 @@ with gr.Blocks() as demo:
 
 ### 📢 系統公告
 """)
-    gr.Markdown(fetch_announcement_from_sheet())
+    announcement_display = gr.Markdown()
+    demo.load(fn=fetch_announcement_from_sheet, inputs=[], outputs=announcement_display)
 
     file_input = gr.File(label="上傳 Evaluation_Dataset.csv")
     api_key_input = gr.Textbox(label="OpenAI API Key", type="password")