Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/6bce1d6..43a4f0e

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

Change-Id: I03b8c3002da073209e092ba1204646ad7f856aeb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3520362
Commit-Queue: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Bot-Commit: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#79454}

DEPS

@@ -83,7 +83,7 @@ deps = {
   'base/trace_event/common':
     Var('chromium_url') + '/chromium/src/base/trace_event/common.git' + '@' + 'd115b033c4e53666b535cbd1985ffe60badad082',
   'build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + '6bce1d637138b472c16d8acb699422d814c78803',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '43a4f0e360da066edc7c4c1078639d4f3df88851',
   'buildtools':
     Var('chromium_url') + '/chromium/src/buildtools.git' + '@' + '113dd1badbcbffea108a8c95ac7c89c22bfd25f3',
   'buildtools/clang_format/script':