Bump third_party/pigweed/repo from 71ba37c to baf04ad

Bumps [third_party/pigweed/repo](https://github.com/google/pigweed) from `71ba37c` to `baf04ad`.
- [Release notes](https://github.com/google/pigweed/releases)
- [Commits](google/pigweed@71ba37c...baf04ad)

---
updated-dependencies:
- dependency-name: third_party/pigweed/repo
  dependency-type: direct:production
...

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