Add fuchsia.stamp for roller (#10293)

tools/fuchsia/build_fuchsia_artifacts.py

@@ -156,6 +156,12 @@ def ProcessCIPDPakcage(upload, engine_version):
     ]
 
   subprocess.check_call(command, cwd=_bucket_directory)
+  if upload and IsLinux():
+    stamp_file_path = os.path.join(_script_dir, 'fuchsia.stamp')
+    stamp_file = open(stamp_file_path, 'w')
+    stamp_file.write('https://chrome-infra-packages.appspot.com/p/flutter/fuchsia/+/git_revision:%s' % engine_version)
+    stamp_file.close()
+    subprocess.check_call('gsutil', 'cp', 'gs://flutter_infra/flutter/%s/' % engine_version, stamp_file_path)
 
 
 def GetRunnerTarget(runner_type, product, aot):