[roll third_party/pigweed] docs: Fix build command typo

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/184170

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: b582d48bcdb6928..303f354624ee666
Roller-URL: https://ci.chromium.org/b/8762398298593366337
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I5e3e2f4920eb5f1595647af5f5eb224ad3bea48d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/184234
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index b582d48..303f354 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit b582d48bcdb6928e53ba3731b567187c6f382b48
+Subproject commit 303f354624ee666ecdec4b8c21b166f574baefe8