build(deps): bump parallel from 1.21.0 to 1.22.0 in /docs

Bumps [parallel](https://github.com/grosser/parallel) from 1.21.0 to 1.22.0.
- [Release notes](https://github.com/grosser/parallel/releases)
- [Commits](https://github.com/grosser/parallel/compare/v1.21.0...v1.22.0)

---
updated-dependencies:
- dependency-name: parallel
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>