Incrementing VERSION to 91.0.4435.4

TBR=srinivassista@chromium.org

Change-Id: I741e9c193e1aa08efb883ae6dbd85796e1b68ba5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2737041
Reviewed-by: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Chrome Release Bot (LUCI) <chrome-official-brancher@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/4435@{#9}
Cr-Branched-From: f3c257e-refs/heads/master@{#859168}

chrome/VERSION

@@ -1,4 +1,4 @@
 MAJOR=91
 MINOR=0
 BUILD=4435
-PATCH=3
+PATCH=4