roll: third_party/pigweed pw_build: Add pw_rust_bindgen

Original-Bug: 365470545

Implement pw_rust_bindgen. A simple test case for generating C bindings
is added.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/234671
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: 1f2a0feb81000531f1ae7e9e26a845609c1beb78

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 819dd2ceb430ea..1f2a0feb810005
Roller-URL: https://ci.chromium.org/b/8735759151501825505
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If8e71eb87872fb96b47e5425133ff33b5ac429b6
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/237911
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 819dd2c..1f2a0fe 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 819dd2ceb430eae53909bea7d5a23c7743ef0fc2
+Subproject commit 1f2a0feb81000531f1ae7e9e26a845609c1beb78