Update changelog.txt for 4.11 release (#1741)
Update changelog.txt for 4.11 release (#1741)

* Update changelog.txt

* Update changelog.txt
AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet