[third_party/pigweed] Roll 6 commits

bc2a4e4cbcf4b94 pw_transfer: Respect user-specified resource size
2c13ea8f2033a76 pw_presubmit: Remove unused presubmit step
2c1ea5ca55a6136 pw_module: Remove README.md check
8425ed014a4751b bazel: Update rust_crates in Bazel WORKSPACE
4f37a0bd3126b44 pw_multibuf: Add MultiBufAllocator interface
710f2337bfb925c pw_digital_io_linux: Introduce new module

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 45fab0df4aca712..bc2a4e4cbcf4b94
Roller-URL: https://ci.chromium.org/b/8754252704383622625
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I2dcde5d28f6135c802096151850cc1584dd66a0c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/195030
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 45fab0d..bc2a4e4 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 45fab0df4aca712c8208a347a1dfb1eebada21d6
+Subproject commit bc2a4e4cbcf4b94f3352a490e10926f8984c1266