roll: third_party/pigweed d2b2644..1997348 (3 commits)

1997348:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/316892 doxygen: Migrate pw_tokenizer
e3e4e1e:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/317395 pw_env_setup: Fix Bazel CIPD cache directory
9ff268c:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/316834 pw_multibuf: Add TryReserveLayers

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: d2b2644598a297..199734872218b5
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8705151833986513761
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7e2f8677c7fc8ffde39beb849bac6ae29b7e32d5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/317692
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 d2b2644..1997348 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit d2b2644598a297cc7d6b2fec16225ea5348e0a31
+Subproject commit 199734872218b568719c21d25b2c4f1dacf457d8