Add ability to pass `deprecated: true` to @endpoints config

[warmbowski]

Is your feature request related to a problem? Please describe.
Using spot @endpoint configuration, I don't see a way to mark and endpoint deprecated: true.

Describe the solution you'd like
Be able to pass deprecated: true to the endpoint decorator config object so that the property appears as a child of the path.method (in the Operation Object) in openapi 2 or 3 generated yaml. (I don't think this would affect other generators).

Describe alternatives you've considered
I can't think of any

Additional context
See Operation Object in these docs
Add to these allowed config props