⬆️ Bump pycryptodome from 3.18.0 to 3.19.1 in /backend (#1087)

Bumps [pycryptodome](https://github.com/Legrandin/pycryptodome) from 3.18.0 to 3.19.1.
- [Release notes](https://github.com/Legrandin/pycryptodome/releases)
- [Changelog](https://github.com/Legrandin/pycryptodome/blob/master/Changelog.rst)
- [Commits](Legrandin/pycryptodome@v3.18.0...v3.19.1)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>