Updating trunk VERSION from 4387.0 to 4388.0

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

Change-Id: Icfc56e5ea80edf8434748822d93c5f6c91922d99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626768Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#842872}

chrome/VERSION

 MAJOR=89
 MINOR=0
-BUILD=4387
+BUILD=4388
 PATCH=0