Remove deprecated `use_relative_hooks = True` from DEPS file.
Remove deprecated `use_relative_hooks = True` from DEPS file.

According to gclient, `use_relative_hooks` is deprecated, since
it was merged into `use_relative_paths`, so delete that line.

Change-Id: Iaa20b8756c4d9f49f9a73dc6b13a46798ab2423d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2316056
Commit-Queue: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>
Commit-Queue: Paul Lewis <8915f5d5c39a08c5a3e8a8d7314756e4580816f9@chromium.org>
Auto-Submit: Benedikt Meurer <024a1e0af501338d11c3b837c6193d11c140d792@chromium.org>
Reviewed-by: Paul Lewis <8915f5d5c39a08c5a3e8a8d7314756e4580816f9@chromium.org>

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