[third_party/pigweed] Roll 2 commits

bb565630a3d48f4 pw_rpc: Update Nanopb serde API for consistency
38d4c76da92e74b pw_rpc: Move fixed properties to a bit field

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: d07c15b6d3222c4..bb565630a3d48f4
Roller-URL: https://ci.chromium.org/b/8792215916631915313
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7d0c6a0e63d4ad712294695a6129c81b2d95d4be
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/126476
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 d07c15b..bb56563 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit d07c15b6d3222c4719af10fd77586b86801759b3
+Subproject commit bb565630a3d48f49e833d237d44406b50561598d