Updating trunk VERSION from 3947.0 to 3948.0

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

Change-Id: I92efd5b68f839b8190f0c7c5d5ee002f3f8b2594
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1873346Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#708083}

chrome/VERSION

 MAJOR=80
 MINOR=0
-BUILD=3947
+BUILD=3948
 PATCH=0