Bump transformers from 4.39.3 to 4.40.0 in /app

Bumps [transformers](https://github.com/huggingface/transformers) from 4.39.3 to 4.40.0.
- [Release notes](https://github.com/huggingface/transformers/releases)
- [Commits](https://github.com/huggingface/transformers/compare/v4.39.3...v4.40.0)

---
updated-dependencies:
- dependency-name: transformers
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/requirements.txt

@@ -4,7 +4,7 @@ diffusers[torch]==0.27.2
 onnxruntime==1.17.3
 safetensors==0.4.3
 torch==2.2.2
-transformers==4.39.3
+transformers==4.40.0
 xformers==0.0.25.post1
 
 realesrgan==0.3.0