build(deps): bump libsodium-sys-stable from 1.20.2 to 1.21.3

Bumps [libsodium-sys-stable](https://github.com/jedisct1/libsodium-sys-stable) from 1.20.2 to 1.21.3.
- [Commits](jedisct1/libsodium-sys-stable@1.20.2...1.21.3)

---
updated-dependencies:
- dependency-name: libsodium-sys-stable
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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