build(deps): bump undici in /.github/actions/send-email (#2521)

Bumps [undici](https://github.com/nodejs/undici) from 5.28.3 to 5.28.4.
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.3...v5.28.4)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]