Bump third_party/pigweed/repo from 7c87569 to d8e4b80

Bumps [third_party/pigweed/repo](https://github.com/google/pigweed) from `7c87569` to `d8e4b80`.
- [Commits](google/pigweed@7c87569...d8e4b80)

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

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