gsutil update default version to 4.30

Bug: 797463
Change-Id: Ia8f565997dfe2180586a8777c51f1f32229dbf3b
Reviewed-on: https://chromium-review.googlesource.com/986922Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>

gsutil.py

@@ -156,7 +156,7 @@ def parse_args():
   bin_dir = os.environ.get('DEPOT_TOOLS_GSUTIL_BIN_DIR', DEFAULT_BIN_DIR)
 
   parser = argparse.ArgumentParser()
-  parser.add_argument('--force-version', default='4.28')
+  parser.add_argument('--force-version', default='4.30')
   parser.add_argument('--clean', action='store_true',
       help='Clear any existing gsutil package, forcing a new download.')
   parser.add_argument('--fallback', default=DEFAULT_FALLBACK_GSUTIL)