Updating trunk VERSION from 5839.0 to 5840.0

* This is an automated release commit.
* Do not revert without consulting chrome-pmo@google.com.
NOAUTOREVERT=true

Change-Id: I6a5f9729c713848ca0d53fd9a599eda7c9577012
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4624848
Bot-Commit: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1159359}

chrome/VERSION

@@ -1,4 +1,4 @@
 MAJOR=116
 MINOR=0
-BUILD=5839
+BUILD=5840
 PATCH=0