Remove deprecated use_relative_hooks reference

Change-Id: Ie035afafda60e10dd728706ad2652399d2a991f1
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/25521
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
diff --git a/DEPS b/DEPS
index fc97620..ab49a29 100644
--- a/DEPS
+++ b/DEPS
@@ -1,5 +1,4 @@
 use_relative_paths = True
-use_relative_hooks = True
 
 gclient_gn_args_file = 'build/config/gclient_args.gni'
 gclient_gn_args = [