Bump uvicorn from 0.23.1 to 0.23.2 in /backend/paaster

Bumps [uvicorn](https://github.com/encode/uvicorn) from 0.23.1 to 0.23.2.
- [Release notes](https://github.com/encode/uvicorn/releases)
- [Changelog](https://github.com/encode/uvicorn/blob/master/CHANGELOG.md)
- [Commits](encode/uvicorn@0.23.1...0.23.2)

---
updated-dependencies:
- dependency-name: uvicorn
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>