Bump torch from 2.5.1 to 2.7.1 in /demo

Bumps [torch](https://github.com/pytorch/pytorch) from 2.5.1 to 2.7.1.
- [Release notes](https://github.com/pytorch/pytorch/releases)
- [Changelog](https://github.com/pytorch/pytorch/blob/main/RELEASE.md)
- [Commits](pytorch/pytorch@v2.5.1...v2.7.1)

---
updated-dependencies:
- dependency-name: torch
  dependency-version: 2.7.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

demo/requirements.txt

@@ -1,4 +1,4 @@
-torch==2.5.1
+torch==2.7.1
 torchvision
 torchaudio