Update Gradio in readme

Gradio version is controlled by readme not only requirements.txt. Must be >3.11 to process files larger than 10mb. See https://huggingface.co/docs/hub/spaces-sdks-gradio , https://github.com/gradio-app/gradio/issues/2700 and and https://discuss.huggingface.co/t/error-connection-errored-out-during-processing/23439

README.md

@@ -4,7 +4,7 @@ emoji: ⚡
 colorFrom: pink
 colorTo: purple
 sdk: gradio
-sdk_version: 3.3.1
+sdk_version: 3.13.0
 app_file: app.py
 pinned: false
 license: apache-2.0