Bump portalocker from 2.10.1 to 3.1.1

Bumps [portalocker](https://github.com/wolph/portalocker) from 2.10.1 to 3.1.1.
- [Release notes](https://github.com/wolph/portalocker/releases)
- [Changelog](https://github.com/wolph/portalocker/blob/develop/CHANGELOG.rst)
- [Commits](wolph/portalocker@v2.10.1...v3.1.1)

---
updated-dependencies:
- dependency-name: portalocker
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

app/backend/requirements.txt

@@ -338,7 +338,7 @@ pillow==10.4.0
     # via
     #   -r requirements.in
     #   openai-messages-token-helper
-portalocker==2.10.1
+portalocker==3.1.1
     # via msal-extensions
 priority==2.0.0
     # via hypercorn