Auto-cc chromiummetricswatch@microsoft.com on changes to metrics.

Add chromium metrics watch alias to metrics watchlist

Change-Id: Iff932b10891ac905a3bc5afd598fe7fb09e063c2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2153929
Auto-Submit: Joshua Berenhaus <joshber@microsoft.com>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760143}

WATCHLISTS

@@ -2577,7 +2577,8 @@
                      'pthatcher+watch@chromium.org',
                      'takumif+watch@chromium.org'],
     'message_loop': ['sadrul@chromium.org'],
-    'metrics': ['asvitkine+watch@chromium.org'],
+    'metrics': ['asvitkine+watch@chromium.org',
+                'chromiummetricswatch@microsoft.com'],
     'metrics_metadata_files': ['asvitkine+watchxml@chromium.org',
                                'chromium-metrics-reviews@google.com'],
     'metrics_perf': ['cwp-reviews+chromium@google.com'],