[roll third_party/pigweed] pw_transfer: Support reads in C++ client

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/95044

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: c70fb56631fa423..d20c1242ea54ac7
Roller-URL: https://ci.chromium.org/b/8813692266735202449
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8813692266735202449
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id34da50d1331540e7aa2475cbb0ff2d0b2216b30
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/95406
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 c70fb56..d20c124 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit c70fb56631fa4231e2a475ac65d819cfb4336947
+Subproject commit d20c1242ea54ac76bbf2104d98b88b52d2919f1e