roll: pigweed, pw_toolchain: pw_async2: Create OnceSender & OnceReceiver

Create a OnceSender/OnceReceiver utility that can be used to
asynchronously send a value.

Original-Bug: b/350994818

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/226231
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>

https://pigweed.googlesource.com/pigweed/pigweed
pigweed, pw_toolchain Rolled-Commits: cc53189f14208ac..14b586f99ceae20
Roller-URL: https://ci.chromium.org/b/8739674398424397393
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iae9dc4492957eff820d8726ec0a8627cb9f2b6db
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/showcase/sense/+/229457
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/MODULE.bazel b/MODULE.bazel
index 552f509..7cdd98b 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -47,18 +47,18 @@
 git_override(
     module_name = "pigweed",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-08-13.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8739678120118658225.
-    commit = "cc53189f14208ac7897872285c547c516706a81e",
+    # ROLL: Last updated 2024-08-14.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8739674398424397393.
+    commit = "14b586f99ceae206334b1b952bdc30bfa2e2e321",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )
 
 git_override(
     module_name = "pw_toolchain",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-08-13.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8739678120118658225.
-    commit = "cc53189f14208ac7897872285c547c516706a81e",
+    # ROLL: Last updated 2024-08-14.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8739674398424397393.
+    commit = "14b586f99ceae206334b1b952bdc30bfa2e2e321",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
     strip_prefix = "pw_toolchain_bazel",
 )