gsutil update default version to 4.30
gsutil update default version to 4.30

Bug: 797463
Change-Id: Ia8f565997dfe2180586a8777c51f1f32229dbf3b
Reviewed-on: https://chromium-review.googlesource.com/986922
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>
Commit-Queue: Caleb Rouleau <58bdb6276c01e3ed53e660bf706aa902204feb0d@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools