roll: gn

From: git_revision:0ae75f90df148d19083055b29c4c940b136904b4
To: git_revision:646a62e029de4827e384c8517dc62fd3c7f85207

CQ-Do-Not-Cancel-Tryjobs: true
Roller-URL: https://ci.chromium.org/b/8862954647188938768
Cq-Cl-Tag: roller-builder:gn-roller
Cq-Cl-Tag: roller-bid:8862954647188938768
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ifef60fd0288e5cc3115e5d56f196ab1017d480d8
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/25680
Reviewed-by: Pigweed Roller <pigweed-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
index 13d0449..2ff98cf 100644
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
@@ -2,7 +2,7 @@
   {
     "path": "gn/gn/${os}-${arch=amd64,arm64}",
     "tags": [
-      "git_revision:0ae75f90df148d19083055b29c4c940b136904b4"
+      "git_revision:646a62e029de4827e384c8517dc62fd3c7f85207"
     ]
   },
   {