list_pipelines() always throws AzureDevOpsAuthenticationError - azure-devops v7.1.0b4

Hi,

I can't get the list of Azure Pipelines because the function list_pipelines() always throws an AzureDevOpsAuthenticationError.

Steps to reproduce the error:

1. Create an Azure DevOps PAT with Full access.
2. Install the version 7.1.0b4: pip install azure-devops==7.1.0b4
3. Replace the parameter values with you PAT and Azure DevOps parameters and run this code:

from azure.devops.connection import Connection
from msrest.authentication import BasicAuthentication

personal_access_token = "PAT"
organization = "contoso"
project = "project-one"

credentials = BasicAuthentication('', personal_access_token)
connection = Connection(base_url=f'https://dev.azure.com/{organization}', creds=credentials)

pipelines_client = connection.clients.get_pipelines_client()
pipelines_list = pipelines_client.list_pipelines(project)

Comece reproduzindo a falha com o snippet Python fornecido usando azure-devops==7.1.0b4 e um PAT válido do Azure DevOps. Rastreie a chamada list_pipelines() pelo cliente de pipelines e pelo tratamento de autenticação; a tarefa estará concluída quando a chamada listar os pipelines sem lançar AzureDevOpsAuthenticationError.