roll: third_party/pigweed c53611c..474f5e4 (4 commits)

474f5e4:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/263934 pw_bluetooth_proxy: Use pw::span_cast
4c87468:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/270833 roll: Clang
cca9290:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/270914 pw_bluetooth_proxy: Add a common WriteLocked on L2capChannel
e83026f:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/270913 docs: Connect upstream guide to contributing

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: c53611c82e2e49..474f5e45163d42
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8721961328461565793
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7d39963a495baed0e451136f59481e5faf6cd727
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/kudzu/+/270952
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index c53611c..474f5e4 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit c53611c82e2e49edd5501bd80c8a431b1986f655
+Subproject commit 474f5e45163d42c7ba0557c65f36259a1ca2b859