Fixing root_files WATCHLIST regex.

Bug: webrtc:9152
Change-Id: I881ebae98063a20b8981b71eb2507545651a3e63
No-Try: True
Reviewed-on: https://webrtc-review.googlesource.com/71024
Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
Commit-Queue: Niklas Enbom <niklas.enbom@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22929}
diff --git a/WATCHLISTS b/WATCHLISTS
index 377c5dc..4eab89f 100644
--- a/WATCHLISTS
+++ b/WATCHLISTS
@@ -20,7 +20,7 @@
     },
     'root_files': {
       # Non-recursive contents of ./
-      'filepath': '^[^/]*$|',
+      'filepath': '^[^/]*$',
     },
     'build_files': {
       'filepath': '\.gni$|\.gn$',