Add win32-arm64-rel to the gitiles trigger.

Bug: 925575
Change-Id: I0fb736af2963b307f6bf141ea1c23ee16b1cf671
Reviewed-on: https://chromium-review.googlesource.com/c/1471249Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632005}

infra/config/luci-scheduler.cfg

@@ -357,6 +357,7 @@ trigger {
   triggers: "win-dbg"
   triggers: "win-jumbo-rel"
   triggers: "win-rel"
+  triggers: "win32-arm64-rel"
   triggers: "win32-dbg"
   triggers: "win32-rel"
 }
@@ -4018,6 +4019,16 @@ job {
   }
 }
 
+job {
+  id: "win32-arm64-rel"
+  acl_sets: "default"
+  buildbucket: {
+    server: "cr-buildbucket.appspot.com"
+    bucket: "luci.chromium.ci"
+    builder: "win32-arm64-rel"
+  }
+}
+
 job {
   id: "win32-dbg"
   acl_sets: "default"