Deps: Bump the python-packages group with 3 updates

Bumps the python-packages group with 3 updates: [certifi](https://github.com/certifi/python-certifi), [librt](https://github.com/mypyc/librt) and [pynacl](https://github.com/pyca/pynacl).


Updates `certifi` from 2025.11.12 to 2026.1.4
- [Commits](certifi/python-certifi@2025.11.12...2026.01.04)

Updates `librt` from 0.7.5 to 0.7.7
- [Commits](mypyc/librt@v0.7.5...v0.7.7)

Updates `pynacl` from 1.6.1 to 1.6.2
- [Changelog](https://github.com/pyca/pynacl/blob/main/CHANGELOG.rst)
- [Commits](pyca/pynacl@1.6.1...1.6.2)

---
updated-dependencies:
- dependency-name: certifi
  dependency-version: 2026.1.4
  dependency-type: indirect
  update-type: version-update:semver-major
  dependency-group: python-packages
- dependency-name: librt
  dependency-version: 0.7.7
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: python-packages
- dependency-name: pynacl
  dependency-version: 1.6.2
  dependency-type: indirect
  update-type: version-update:semver-patch
  dependency-group: python-packages
...

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

Author: dependabot[bot]