Using Azure OpenAI with AAD example broken link in OpenAI v1 Release Notes Discussion

[achandmsft]

#631 links to https://github.com/openai/openai-python/blob/v1/examples/azure_ad.py

Fix: Should be https://github.com/openai/openai-python/blob/main/examples/azure_ad.py

[RobertCraigie]

Thanks for the report! I've updated the link in the discussion.