Bump undici from 7.16.0 to 7.20.0 in /docs

Bumps [undici](https://github.com/nodejs/undici) from 7.16.0 to 7.20.0.
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v7.16.0...v7.20.0)

---
updated-dependencies:
- dependency-name: undici
  dependency-version: 7.20.0
  dependency-type: indirect
...

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Author: dependabot[bot]