roll: third_party/pigweed 813fe27..2ac8a3a (3 commits)

2ac8a3a:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/268055 pw_kernel: Add timer based preemption
70d2e87:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/269295 pw_presubmit: Disregard file order in PyPI upload
78a55c8:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/269212 pw_assert: Narrow some dependencies

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 813fe272d52a81..2ac8a3ac33fac5
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8722411815407757969
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I9a1f621454bedecb469aade25b5233cfd66f2caa
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/kudzu/+/269472
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 813fe27..2ac8a3a 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 813fe272d52a81bbeb774a3d307086138db7bf8b
+Subproject commit 2ac8a3ac33fac50337152da174d40a73a49aa85a