Updating trunk VERSION from 3946.0 to 3947.0

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

Change-Id: Ifeae3de0eca36ffdc24fb26797df35c2e89d1dbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869722Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#707629}

chrome/VERSION

 MAJOR=80
 MINOR=0
-BUILD=3946
+BUILD=3947
 PATCH=0