Updating trunk VERSION from 4254.0 to 4255.0

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

Change-Id: I2f067b3b5ca733b26ea355cad8ae110e28e9f705
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2393516Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#804513}

chrome/VERSION

 MAJOR=87
 MINOR=0
-BUILD=4254
+BUILD=4255
 PATCH=0