Release Event Hub Track 2 Library Preview 1

[AlexGhiondea]

Goal

Release the Event Hub Track 2 library.

• Repo Readiness (Revise setup.py #5114, Revise readme #5110 )
• Docs and Samples Readiness (Revise docstrings #5113 , Revise sample code #5112)
• Track 2 Guidelines Requirements
  • Authentication (Align authentication to the new patterns #5101)
  • Logging and Tracing (Review and revise logging #5085)
  • Error Hierarchy patterns (Align error hierarchy to patterns defined in the guidelines #5100)
  • Async namespace (Move async code to package aio #5081 )
  • Retry and cancellations (Review and revise retry, cancellation and timeouts #5084)
  • Context manager to open and close connection (Context Manager to open and close connection #5098)
  • Expose configuration settings in a config class (Expose configuration settings in a configuration class #5099) -- changed to use kwargs intead of config class
  • Iterator-like interface to replace callback (Create an iterator-like interface for working with events to replace the less-python callback like interface #5102)
• New features
  • Websocket and proxy support (Add websocket support to uAMQP and Event Hubs #5071, Full proxy support to configuration #5103, Add test cases for websocket and proxy #5106)
  • OAuth support (Add oauth support to uAMQP #5097, Add test cases for oauth #5107)
  • Get partition information (Add get_partition_info method in Event Hub Client #5324)

[yunhaoling]

• released package on pypi: https://pypi.org/project/azure-eventhub/5.0.0b1/
• release notes: https://github.com/Azure/azure-sdk/blob/master/docs/release-notes/preview/summary-preview1-python.md