roll: third_party/pigweed 20b31f0..508ae91 (2 commits)

508ae91:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/434637 pw_bluetooth_sapphire: Cap L2CAP pre-activation SDU queue
a34b673:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/440772 pw_sync_zephyr: Use quote includes for Pigweed headers

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 20b31f0f04da6b..508ae91e0eca56
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8675514662665339793
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I363b0f5583b82c741c39401696149269cfb92af2
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/440686
diff --git a/third_party/pigweed b/third_party/pigweed
index 20b31f0..508ae91 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 20b31f0f04da6b0831adacd853ebdc985cb9e0f5
+Subproject commit 508ae91e0eca560ade97099c2997bc383932e56d