[roll third_party/pigweed] docs: Add Bazel getting started tutorial

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/176319

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 724fe756ce247ee..788d0f28e960253
Roller-URL: https://ci.chromium.org/b/8766781671562341345
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id32a5a9caf7b070fb09c8083a629ead1c411dd17
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/177012
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 724fe75..788d0f2 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 724fe756ce247ee49addab1afdd5412da1afc989
+Subproject commit 788d0f28e96025385408a20d717728dfd996a909