Updating trunk VERSION from 3907.0 to 3908.0

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

Change-Id: Icf2f0bea8f4a5cd0a2999fb54c497592a68904fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790301Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#694637}

chrome/VERSION

 MAJOR=79
 MINOR=0
-BUILD=3907
+BUILD=3908
 PATCH=0