The example with "localhost" and "uname" is broken

[PPPW]

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Describe the bug
The example in the README is broken:

from pssh.clients import ParallelSSHClient

hosts = ['localhost', 'localhost']
client = ParallelSSHClient(hosts)

output = client.run_command('uname')

To Reproduce
Run the above example.

Expected behavior
The above code runs successfully.

Actual behaviour
The above code got exception:

Traceback (most recent call last):
  File "/home/azureuser/.local/lib/python3.10/site-packages/pssh/clients/base/single.py", line 204, in _auth_retry
    self.auth()
  File "/home/azureuser/.local/lib/python3.10/site-packages/pssh/clients/base/single.py", line 364, in auth
    return self._identity_auth()
  File "/home/azureuser/.local/lib/python3.10/site-packages/pssh/clients/base/single.py", line 337, in _identity_auth
    raise AuthenticationError("No authentication methods succeeded")
pssh.exceptions.AuthenticationError: No authentication methods succeeded
...
pssh.exceptions.AuthenticationError: ('Authentication error while connecting to %s:%s - %s - retries %s/%s', 'localhost', 22, AuthenticationError('No authentication methods succeeded'), 3, 3)

Additional information
The issue happens when no auth is needed, e.g., SSH to localhost, or to a host without the need of -i. The ParallelSSHClient's constructor takes identity_auth=False, however with that, in /pssh/clients/base/single.py, it will try to do password auth, which also doesn't apply. This looks like a regression. Could you fix that and support uses cases that auth is not needed? Thank you!

[christiankotait]

Same issue. Can you please fix this?