Upload official jamf file to GCS.

The file is not in an archive, since it is convenient for the release
tool to be able to copy it directly to the download server (instead of
unzipping it, saving it back to GCS, then copying it to the download
server).

Bug: 1058102
Change-Id: I487afbdc5587fe0f36f400af5b3c070a8850f349
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2374513
Auto-Submit: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801386}

chrome/tools/build/mac/FILES.cfg

@@ -146,4 +146,10 @@ FILES = [
     'archive': 'updater.zip',
     'optional': ['official'], # TODO(crbug.com/1024318): Make non-optional.
   },
+  # Enterprise policy templates:
+  {
+    'filename': 'gen/chrome/app/policy/mac/jamf.json',
+    'buildtype': ['official'],
+    'optional': ['official'],
+  }
 ]