Incrementing VERSION to 78.0.3904.6

TBR=mmoss@chromium.org

Change-Id: I5cb4f858a58f89abbc560fa0b2742b028152cf2e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790495
Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/3904@{#11}
Cr-Branched-From: 675968a8c657a3bd9c1c2c20c5d2935577bbc5e6-refs/heads/master@{#693954}
1 file changed