Incrementing VERSION to 78.0.3874.2

TBR=benmason@chromium.org

Change-Id: I2a0894a94de791e5c8bf78311574d4f0c02a6643
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1735588
Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/3874@{#4}
Cr-Branched-From: c5e02adbec8edc0e2280b95b3fbd7f53a7406eeb-refs/heads/master@{#683858}
1 file changed