Bump jwcrypto from 1.5.0 to 1.5.6 in /backend

Bumps [jwcrypto](https://github.com/latchset/jwcrypto) from 1.5.0 to 1.5.6.
- [Release notes](https://github.com/latchset/jwcrypto/releases)
- [Commits](latchset/jwcrypto@v1.5.0...v1.5.6)

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

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