Add support for type variable #274

Is your feature request related to a problem? Please describe.
According to https://developer.nylas.com/docs/api/v3/scheduler/#tag/configurations/POST/v3/grants/%7Bgrant_id%7D/scheduling/configurations
There is a type value that takes in
collective
group
max-availability
max-fairness
one-on-one

There is currently no way to pass in this value.

Describe the solution you'd like
Have the ability to pass in this value.

Describe alternatives you've considered
Right now I have to subclass this class and pass it in

Additional context
I am happy to implement this and contribute to the codebase.