[roll third_party/pigweed] pw_rpc: Allow using enums for channel IDs

This adds a Channel::Create overload which accepts an enum ID value, to
allow cleaner organization of channel IDs.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/40320

third_party/pigweed Rolled-Commits: 6f5b8fb1ff9a8b2..1c670a2693ab23c
Roller-URL: https://ci.chromium.org/b/8850402817848978864
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8850402817848978864
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iffbadc5f18d49fb5fe01efdce985396a3a8574a5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/40380
Reviewed-by: 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 6f5b8fb..1c670a2 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 6f5b8fb1ff9a8b2e025863187c7ec7c46fa74929
+Subproject commit 1c670a2693ab23c6d890f1f8d2310ba2b9db72ec