roll: third_party/pigweed pw_sync_zephyr.mutex_backend: add pw_assert as public dep

the HEADERS of this module (public/pw_sync_zephyr/mutex_inline.h),
includes "pw_assert/assert.h" as dependency,
however, this dependency is not included in CMakeLists.txt,
thereby, when I as linking against this library, this module failed to
compile.

Adding `pw_assert` fix this problem.

Tested: build pass
Google-Bug-Id: 526827174
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/435073
Original-Revision: 37d76cad8fb26ecce3504eb1a9cffd30b03d8627

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: f90f2c0d943e5f..37d76cad8fb26e
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8676366384189001441
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I02ebadf61dcc2e1bdaee1e2cdee1f61e576a50d3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/435512
diff --git a/third_party/pigweed b/third_party/pigweed
index f90f2c0..37d76ca 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit f90f2c0d943e5fd1f0581f1b7a4a85bed20a7f40
+Subproject commit 37d76cad8fb26ecce3504eb1a9cffd30b03d8627