Add support for PingOne

[primetheus]

One of the major SAML identity providers is PingOne. It would be useful for this app to have the ability to synchronize groups with GitHub

[primetheus]

API reference for group members: https://apidocs.pingidentity.com/pingone/platform/v1/api/#groups

[primetheus]

potential library that could be used: https://github.com/pingidentity/pingid-python-samples