Updating trunk VERSION from 3660.0 to 3661.0

# This is an automated release commit.
# Do not revert without consulting chrome-pmo@google.com.
NOAUTOREVERT=true
TBR=benmason@chromium.org

Change-Id: I6ee0054c1dc9ed5018108b21c6f503444284abca
Reviewed-on: https://chromium-review.googlesource.com/c/1394424Reviewed-by: chrome-release-bot@chromium.org <chrome-release-bot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619582}

chrome/VERSION

 MAJOR=73
 MINOR=0
-BUILD=3660
+BUILD=3661
 PATCH=0