Updating trunk VERSION from 4306.0 to 4307.0

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

Change-Id: I3a8aeaa55b43e14bcc12619bce05470d5c3c208e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2504651Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#821585}

chrome/VERSION

 MAJOR=88
 MINOR=0
-BUILD=4306
+BUILD=4307
 PATCH=0