Bump third_party/pigweed/repo from `e35aa3a` to `c8c31a0` (#30924)

Bumps [third_party/pigweed/repo](https://github.com/google/pigweed) from `e35aa3a` to `c8c31a0`.
- [Commits](https://github.com/google/pigweed/compare/e35aa3aecf78ae4914e9559b77c57885a548a23d...c8c31a063f54a11ffdc32635c2d516876f4cc94b)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/pigweed/repo b/third_party/pigweed/repo
index e35aa3a..c8c31a0 160000
--- a/third_party/pigweed/repo
+++ b/third_party/pigweed/repo
@@ -1 +1 @@
-Subproject commit e35aa3aecf78ae4914e9559b77c57885a548a23d
+Subproject commit c8c31a063f54a11ffdc32635c2d516876f4cc94b