[Release] Automatically notify mailing list on a pending merge

WATCHLISTS

Index: WATCHLISTS
diff --git a/WATCHLISTS b/WATCHLISTS
index 29b957b0917f0034bdb2f9378f93d0d9435cc5fc..f0dde00dba0c195c74bf070954fe5c132a2c14df 100644
--- a/WATCHLISTS
+++ b/WATCHLISTS
@@ -60,6 +60,9 @@
     },
     'ia32': {
       'filepath': '/ia32/',
+    },
+    'merges': {
+      'filepath': '.',
     }
   },
 
@@ -91,5 +94,9 @@
     'ia32': [
       'v8-x87-ports@googlegroups.com',
     ],
+    'merges': [
+      # Only enabled on branches created with tools/release/create_release.py
+      # 'v8-merges@googlegroups.com',
+    ],
   },
 }