Bump third_party/pigweed/repo from c8c31a0 to 355d707

Bumps [third_party/pigweed/repo](https://github.com/google/pigweed) from `c8c31a0` to `355d707`.
- [Commits](google/pigweed@c8c31a0...355d707)

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

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