[roll third_party/pigweed] pw_env_setup: Add placeholder arm.json file

Original-Bug: 599
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/80600

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 5702eeb4da6f2b3..3367d2eb8028453
Roller-URL: https://ci.chromium.org/b/8824468579822557121
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8824468579822557121
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia1a4ca76890556198234fe4c76fbfdd5aea846db
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/80642
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 5702eeb..3367d2e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 5702eeb4da6f2b30bd2b75187cecd240b4ee5dc7
+Subproject commit 3367d2eb80284531eba875daec92555309eaea76