Usage of creds parameter is deprecated in msrest service client

[jfthuong]

The getting started provides the following code to establish a connection

# Create a connection to the org
credentials = BasicAuthentication('', personal_access_token)
connection = Connection(base_url=organization_url, creds=credentials)

However, while running this code, the following warning is raised:

c:\python37-32\lib\site-packages\msrest\service_client.py:260: DeprecationWarning: Creds parameter is deprecated. Set config.credentials instead.
    DeprecationWarning)

The example in Getting Started could be updated to provide the new way of setting the credentials.

[tedchamb]

Fixed in #198

[tedchamb]

Fixed in 5.0.0b4
https://github.com/Microsoft/azure-devops-python-api/releases/tag/5.0.0b4