[Updater] Send email with only relative path

Test: local run
Change-Id: I1924a07058524eb0bf034dae541a8171e6287f1b
diff --git a/notifier.py b/notifier.py
index 4391558..455a5b9 100644
--- a/notifier.py
+++ b/notifier.py
@@ -134,7 +134,7 @@
     _process_results(args, history, results)
 
     with open(args.history, 'w') as f:
-        json.dump(history, f, sort_keys=True)
+        json.dump(history, f, sort_keys=True, indent=4)
 
 
 def _upgrade(proj):