[roll third_party/pigweed] pw_rpc: Add missing pw_log dependency for CMake

When trying to build a simple CMake project with pw_rpc I found that
I was getting errors importing "pw_log/log.h". This change fixes the
error. It seems that this dependency is included in the BUILD.gn files
and was missing in the CMakeLists.txt

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/65380

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 08956abf0da4bc4..e4dd0d71f074ce1
Roller-URL: https://ci.chromium.org/b/8833474539695322337
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8833474539695322337
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I4751e51398c4db54578c73a207657615c78ff4f6
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/65441
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 08956ab..e4dd0d7 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 08956abf0da4bc431063b39b3151ea58766ab390
+Subproject commit e4dd0d71f074ce149089b5722619b016e0502ad6