Updating trunk VERSION from 4283.0 to 4284.0

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

Change-Id: I15af93256e3a5f54c8f43ec854b675081b8233e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2448677Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#813613}

chrome/VERSION

 MAJOR=88
 MINOR=0
-BUILD=4283
+BUILD=4284
 PATCH=0