Update dependencies

Among others, this updates minio-go, so that the new "eu-west-3" zone
for AWS is supported.

vendor/cloud.google.com/go/storage/doc.go

@@ -23,8 +23,6 @@ All of the methods of this package use exponential backoff to retry calls
 that fail with certain errors, as described in
 https://cloud.google.com/storage/docs/exponential-backoff.
 
-Note: This package is in beta.  Some backwards-incompatible changes may occur.
-
 
 Creating a Client