Bump gradio from 3.32.0 to 3.34.0 in /demo

Bumps [gradio](https://github.com/gradio-app/gradio) from 3.32.0 to 3.34.0.
- [Release notes](https://github.com/gradio-app/gradio/releases)
- [Changelog](https://github.com/gradio-app/gradio/blob/main/CHANGELOG.md)
- [Commits](https://github.com/gradio-app/gradio/compare/v3.32.0...v3.34.0)

---
updated-dependencies:
- dependency-name: gradio
dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

demo/requirements.txt

@@ -1,2 +1,2 @@
 livermask @ git+https://github.com/andreped/livermask.git
-gradio==3.32.0
+gradio==3.34.0