Use arm.json CIPD file

See also http://pwrev/80600 and http://pwrev/78880.

Change-Id: Iaf82eabe72261ae63177180f39ed299f3a7683fd
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/80641
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/env_setup.json b/env_setup.json
index 36ff580..8ce3323 100644
--- a/env_setup.json
+++ b/env_setup.json
@@ -2,6 +2,7 @@
   "root_variable": "SAMPLE_PROJECT_ROOT",
   "cipd_package_files": [
     "third_party/pigweed/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json",
+    "third_party/pigweed/pw_env_setup/py/pw_env_setup/cipd_setup/arm.json",
     "third_party/pigweed/pw_env_setup/py/pw_env_setup/cipd_setup/bazel.json",
     "third_party/pigweed/pw_env_setup/py/pw_env_setup/cipd_setup/python.json",
     "third_party/pigweed/pw_env_setup/py/pw_env_setup/cipd_setup/luci.json"