Bump undici

Bumps  and [undici](https://github.com/nodejs/undici). These dependencies needed to be updated together.

Updates `undici` from 5.28.4 to 6.21.1
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.4...v6.21.1)

Updates `undici` from 6.21.0 to 6.21.1
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.4...v6.21.1)

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

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