Expose is_domain_connection on Connection

[amummaprojectmanager]

Checklist

• I have looked into the Readme and have not found a suitable solution or answer.
• I have looked into the API documentation and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Describe the problem you'd like to have solved

is_domain_connection is an option but it doesn't seem to exist on ConnectionUpdateRequest which just inherits ConnectionBase

Describe the ideal solution

Add the property - I'll raise a PR shortly after double checking this one

Alternatives and current workarounds

No response

Additional context

No response

[frederikprijck]

Thanks for the PR!