update beta relese 4.20.0 change log (#24275)
update beta relese 4.20.0 change log (#24275)

Co-authored-by: annie-mac <92173f0aff2f889e8dd79a432f26d04891c656e9@DESKTOP-62QAK4R.redmond.corp.microsoft.com>
Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java,Azure/azure-sdk-for-java