Bump third_party/pigweed/repo from 8659ed5 to 4b50d0e

Bumps [third_party/pigweed/repo](https://github.com/google/pigweed) from `8659ed5` to `4b50d0e`.
- [Release notes](https://github.com/google/pigweed/releases)
- [Commits](google/pigweed@8659ed5...4b50d0e)

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

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