Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/a169c19..6476f40

TBR=v8-waterfall-sheriff@grotations.appspotmail.com,mtv-sf-v8-sheriff@grotations.appspotmail.com

Change-Id: I7f9fa264560e7a5128358e1b0218cb6763f9c12c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3184927Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#77075}

DEPS

@@ -95,7 +95,7 @@ deps = {
   'base/trace_event/common':
     Var('chromium_url') + '/chromium/src/base/trace_event/common.git' + '@' + '715537d6007ca71837f48bcb04fc3d482aed2507',
   'build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'a169c196997a81ffb80db0422eeb4d22c6855b17',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '6476f40242960303ea3aa0d0c12f39cb7739b85b',
   'buildtools':
     Var('chromium_url') + '/chromium/src/buildtools.git' + '@' + '9d33a7111785c29f91e831d0ad3b01e04d7229ca',
   'buildtools/clang_format/script':