Log in to Unity 5.x Rest API with Invoke-RestMethod

How do I connect to the Unity REST API with Invoke-RestMethod. I can connect with the Postman client with no problem. I must use Powershell as my REST client and choose to use the Invoke-RestMethod as opposed to Invoke-WebRequest. I found an article about this but it points to some websites that explain the solution with an old version of Unity and Powershell. There must be an easier way to do this by now.

https://www.dell.com/community/Unity/EMC-Unity-OE-and-Powershell-REST-login/td-p/7158943