Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/80a5599..908ea81

TBR=machenbach@chromium.org,tmrts@chromium.org,v8-waterfall-sheriff@grotations.appspotmail.com

Change-Id: Iaa95742acd71c233dc06f7335e3f03fb64feb89e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2245216Reviewed-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/master@{#68332}

DEPS

@@ -72,7 +72,7 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + '80a55990fac15e34f44513209c31ef326ce1d04b',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '908ea81374add4a90badc005c5c85fed5b0e6798',
   'v8/third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + '03705f60de6cc7b06ddaabe9649c14fb70b62c4e',
   'v8/third_party/icu':