Version 3 needs access to bucket "default" to connect

Old Python library supported a way to authenticate when there were arbitrary bucket names. When there is only bucket 'bucket-name', I can still use this with version 2.5

>>> from couchbase.cluster import Cluster, PasswordAuthenticator
>>> cluster = Cluster('couchbase://localhost')
>>> cluster.authenticate(PasswordAuthenticator('username', 'password'))
>>> bucket = cluster.open_bucket('bucket-name')

That works perfectly fine.

However, when I try the example from version 3.0

>>> from couchbase.cluster import Cluster, PasswordAuthenticator, ClusterOptions
>>> from couchbase.auth import PasswordAuthenticator
>>> cluster = Cluster('couchbase://localhost', ClusterOptions(PasswordAuthenticator('username', 'password')))
>>> bucket = cluster.bucket('bucket-name')
>>> collection = bucket.default_collection()

it fails on line with Cluster() and URI. It tries to connect to bucket "default" based on couchbase/management/admin.py:87. Its caller in couchbase/cluster.py:518 doesn't allow specification of the bucket. That is called from couchbase/cluster.py:533.

Request: please add a way to connect when there is no "default" bucket.