Bump jose from 4.14.4 to 4.15.5 in /backend

Bumps [jose](https://github.com/panva/jose) from 4.14.4 to 4.15.5.
- [Release notes](https://github.com/panva/jose/releases)
- [Changelog](https://github.com/panva/jose/blob/v4.15.5/CHANGELOG.md)
- [Commits](panva/jose@v4.14.4...v4.15.5)

---
updated-dependencies:
- dependency-name: jose
  dependency-type: indirect
...

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