Bump s3transfer from 0.11.4 to 0.13.0 in /backend

Bumps [s3transfer](https://github.com/boto/s3transfer) from 0.11.4 to 0.13.0.
- [Changelog](https://github.com/boto/s3transfer/blob/develop/CHANGELOG.rst)
- [Commits](https://github.com/boto/s3transfer/compare/0.11.4...0.13.0)

---
updated-dependencies:
- dependency-name: s3transfer
  dependency-version: 0.13.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

backend/requirements.txt

@@ -44,7 +44,7 @@ python-dateutil==2.9.0.post0
 python-dotenv==1.1.0
 requests==2.32.3
 rich==14.0.0
-s3transfer==0.11.4
+s3transfer==0.13.0
 six==1.17.0
 sniffio==1.3.1
 sortedcontainers==2.4.0