Updating trunk VERSION from 3983.0 to 3984.0

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

Change-Id: I7f0df9a128c573a414b94936def27c72ecaf3cf1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1945889Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#720385}

chrome/VERSION

 MAJOR=80
 MINOR=0
-BUILD=3983
+BUILD=3984
 PATCH=0